Method and apparatus for processing user plane data

ABSTRACT

Provided are a method and apparatus for processing user plane data by a terminal. The method may include: receiving additional configuration information for additionally configuring a WLAN carrier using an unlicensed frequency band; receiving downlink user plane data through a base station carrier using the WLAN carrier or a licensed frequency band according to the additional configuration information; and transmitting included uplink user plane data through the WLAN carrier or the base station carrier according to the additional configuration information.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Divisional of pending U.S. patentapplication Ser. No. 15/511,296 (filed on Mar. 15, 2017), which is aNational Stage Patent Application of PCT International PatentApplication No. PCT/KR2015/009741 (filed on Sep. 16, 2015) under 35U.S.C. § 371, which claims priority to Korean Patent Application Nos.10-2014-0124570 (filed on Sep. 18, 2014), 10-2014-0133265 (filed on Oct.2, 2014), 10-2015-0067822 (filed on May 15, 2015), 10-2015-0114273(filed on Aug. 13, 2015), and 10-2015-0114278 (filed on Aug. 13, 2015),the teachings of which are incorporated herein in their entireties byreference.

TECHNICAL FIELD

The present disclosure relates to a method and an apparatus forprocessing user plane data by a terminal and a base station. Morespecifically, the present disclosure relates to a method and anapparatus for transmitting and receiving user plane data by adding awireless local area network (WLAN) to an evolved UMTS terrestrial radioaccess network (E-UTRAN) carrier in a radio access network (RAN) level.

BACKGROUND ART

Due to advance in a communication system, various types of wirelessterminals have been introduced to consumers, such as companies andindividuals. The current 3^(rd) generation partnership project (3GPP)family of mobile communication systems, such as LTE (Long TermEvolution) or LTE-Advanced, is a high-speed and large-capacitycommunication system. Such a communication system can provide a servicefor transmitting and receiving a various types of data, such as imagesor wireless data, as well as a voice data. Accordingly, there is demandfor developing technology for transmitting a large amount of data at ahigh speed as fast as transmission in a wired communication network. Fortransmitting a large amount of data at a high speed, data may beefficiently transmitted by using a plurality of cells.

However, a base station has a limitation to provide a communicationservice to a plurality of terminals. For example, a base station useslimited frequency resources to provide a communication service to aplurality of terminals with a large amount of data. Because of thelimited frequency resources, a communication service provider (e.g.,carrier) needs to secure exclusive frequency resources, and suchsecurement of frequency resources may require a high cost.

Meanwhile, an unlicensed frequency band is not allowed to be exclusivelyused by a specific communication service provider. The unlicensedfrequency band may be shared by a plurality of communication serviceproviders or communication systems. For example, a wireless local areanetwork (WLAN) technology (e.g., WiFi) provides a datatransmission/reception service by using frequency resources of theunlicensed band.

Therefore, it is required to develop technology for enabling a mobilecommunication system to transmit and receive data by using an accesspoint (AP) of the corresponding WiFi.

DETAILED DESCRIPTION OF THE INVENTION Technical Problem

The present disclosure has been made based on such a background, andprovides a downlink data transmission method of a base station and anuplink data transmission method of a terminal when the base station andthe terminal transmit and receive data by using a WLAN carrier.

In addition, the present disclosure provides a detailed method andapparatus for configuring data transmitting/receiving paths to bedifferent for each bearer when the terminal and the base stationtransmit and receive data by configuring a WLAN carrier.

In addition, the present disclosure provides a method and apparatus foridentifying a safe transfer of data even when the base station and theterminal transmit and receive data by using a WLAN carrier.

In addition, the present disclosure provides a method and apparatus forperforming a Packet Data Convergence Protocol (PDCP) function in theE-UTRAN, similar to performing the PDCP in a WLAN carrier.

Technical Solution

The present disclosure to solve the problems above provides a method forprocessing user plane data by a terminal, which may include: receivingadditional configuration information to further configure a WLAN carrierthat uses an unlicensed frequency band; receiving downlink user planedata through the WLAN carrier or through a base station carrier thatuses a licensed frequency band according to the additional configurationinformation; and transmitting included uplink user plane data throughthe WLAN carrier or through the base station carrier according to theadditional configuration information.

In addition, the present disclosure provides a method for processinguser plane data by a base station, which may include: creating andtransmitting additional configuration information to further configure aWLAN carrier that uses an unlicensed frequency band; transmittingdownlink user plane data through the WLAN carrier or through a basestation carrier that uses a licensed frequency band according to theadditional configuration information; and receiving uplink user planedata through the WLAN carrier or through the base station carrieraccording to the additional configuration information.

In addition, the present disclosure provides a terminal for processinguser plane data, which may include: a receiving unit that is configuredto receive additional configuration information to further configure aWLAN carrier that uses an unlicensed frequency band, and is configuredto receive downlink user plane data through the WLAN carrier or througha base station carrier that uses a licensed frequency band according tothe additional configuration information; and a transmitting unit thatis configured to transmit included uplink user plane data through theWLAN carrier or through the base station carrier according to theadditional configuration information.

In addition, the present disclosure provides a base station forprocessing user plane data, which may include: a transmitting unit thatis configured to create and transmit additional configurationinformation to further configure a WLAN carrier that uses an unlicensedfrequency band, and is configured to transmit downlink user plane datathrough the WLAN carrier or through a base station carrier that uses alicensed frequency band according to the additional configurationinformation; and a receiving unit that is configured to receive uplinkuser plane data through the WLAN carrier or through the base stationcarrier according to the additional configuration information.

In addition, the present disclosure provides a method for processingdata by a terminal, which may include: configuring an interface and auser plane entity for transmitting and receiving data to and from a basestation through a WLAN carrier; receiving user plane data from the basestation through the interface; and transmitting control informationindicating the successful or unsuccessful reception of the user planedata to the base station through the interface or through the interfacebetween the terminal and the base station. The present disclosureprovides a method in which the user plane entity is configured to beassociated with each data radio bearer. In addition, the method of thepresent disclosure may further include receiving radio bearerconfiguration information that includes configuration information forconfiguring the user plane entity through an upper layer signaling. Thepresent disclosure provides a method in which the control information isprovided in the user plane entity or the PDCP entity. The presentdisclosure provides a method in which the transmission of the controlinformation is triggered based on at least one of a polling of the basestation or a period or timer that is set by the base station.

In addition, the present disclosure provides a method for processingdata by a base station, which may include: configuring an interface anda user plane entity for transmitting and receiving data to and from aterminal through a WLAN carrier; transmitting user plane data to theterminal through the interface; and receiving control informationindicating the successful or unsuccessful reception of the user planedata from the terminal through the interface or through the interfacebetween the terminal and the base station. The present disclosureprovides a method in which the user plane entity is configured to beassociated with each data radio bearer. In addition, the method of thepresent disclosure may further include transmitting radio bearerconfiguration information that includes configuration information forconfiguring the user plane entity through an upper layer signaling. Thepresent disclosure provides a method in which the control information isprovided in the user plane entity or the PDCP entity of the terminal.The present disclosure provides a method in which the transmission ofthe control information is triggered based on at least one of a pollingof the base station or a period or timer that is set by the basestation.

In addition, the present disclosure provides a terminal for processingdata that may include: a controller that is configured to configure aninterface and a user plane entity for transmitting and receiving data toand from a base station through a WLAN carrier; a receiving unit that isconfigured to receive user plane data from the base station through theinterface; and a transmitting unit that is configured to transmitcontrol information indicating the successful or unsuccessful receptionof the user plane data to the base station through the interface orthrough the interface between the terminal and the base station. Thepresent disclosure provides a terminal in which the user plane entity isconfigured to be associated with each data radio bearer. In addition,the present disclosure provides a terminal that further executestransmitting radio bearer configuration information that includesconfiguration information for configuring the user plane entity throughan upper layer signaling. The present disclosure provides a terminal inwhich the control information is provided in the user plane entity orthe PDCP entity of the terminal. The present disclosure provides aterminal in which the transmission of the control information istriggered based on at least one of a polling of the base station or aperiod or timer that is set by the base station.

In addition, the present disclosure provides a base station forprocessing data that may include: a controller that is configured toconfigure an interface and a user plane entity for transmitting andreceiving data to and from a terminal through a WLAN carrier; atransmitting unit that is configured to transmit user plane data to theterminal through the interface; and a receiving unit that is configuredto receive control information indicating the successful or unsuccessfulreception of the user plane data from the terminal through the interfaceor through the interface between the terminal and the base station. Thepresent disclosure provides a base station in which the user planeentity is configured to be associated with each data radio bearer. Inaddition, the present disclosure provides the base station that furtherexecutes transmitting radio bearer configuration information thatincludes configuration information for configuring the user plane entitythrough an upper layer signaling. The present disclosure provides a basestation in which the control information is provided in the user planeentity or the PDCP entity of the terminal. The present disclosureprovides a base station in which the transmission of the controlinformation is triggered based on at least one of a polling of the basestation or a period or timer that is set by the base station.

Advantageous Effects

The present disclosure described above has an effect of providing adownlink data transmission method of a base station and an uplink datatransmission method of a terminal when the base station and the terminaltransmit and receive data by using a WLAN carrier.

In addition, the present disclosure has an effect of providing adetailed method and apparatus for configuring datatransmission/reception paths to be different for each bearer when theterminal and the base station transmit and receive data by configuring aWLAN carrier.

In addition, the present disclosure gives an effect for operating thetypical PDCP function in the same manner even when the base station andthe terminal transmit and receive data by adding a WLAN carrier.

In addition, the present disclosure gives an effect of transmitting datain sequence without duplicately using the sequence numbers even when thebase station and the terminal transmit and receive data by adding a WLANcarrier.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view exemplary illustrating a configuration diagram of Layer2 for the downlink, according to at least one embodiment of the presentdisclosure;

FIG. 2 is a view exemplary illustrating a configuration diagram of Layer2 for the downlink, according to another embodiment of the presentdisclosure;

FIG. 3 is a view exemplary illustrating a configuration diagram of Layer2 for the downlink in a split structure, according to at least oneembodiment of the present disclosure;

FIG. 4 is a view exemplary illustrating a configuration diagram of Layer2 for the downlink in a split structure, according to another embodimentof the present disclosure;

FIG. 5 is a view exemplary illustrating a configuration diagram of Layer2 for the downlink in an interworking structure, according to at leastone embodiment of the present disclosure;

FIG. 6 is a view exemplary illustrating a configuration diagram of Layer2 for the downlink in an interworking structure, according to anotherembodiment of the present disclosure;

FIG. 7 is a view exemplary illustrating a configuration diagram of Layer2 for downlink in an interworking structure, according to still anotherembodiment of the present disclosure;

FIG. 8 is a view exemplary illustrating a configuration diagram of Layer2 for downlink in an interworking structure, according to yet anotherembodiment of the present disclosure;

FIG. 9 is a view exemplary illustrating a configuration diagram of Layer2 for the uplink, which is configured with the WLAN aggregation or theWLAN interworking in accordance with at least one embodiment of thepresent disclosure;

FIG. 10 is a view exemplary illustrating a configuration diagram ofLayer 2 for the uplink, which is configured with the WLAN aggregation orthe WLAN interworking in accordance with another embodiment of thepresent disclosure;

FIG. 11 is a view exemplary illustrating a configuration diagram ofLayer 2 for the uplink, which is configured with the WLAN aggregation orthe WLAN interworking in accordance with still another embodiment of thepresent disclosure;

FIG. 12 is a view exemplary illustrating a configuration diagram ofLayer 2 for the uplink, which is configured with the WLAN aggregation orthe WLAN interworking in accordance with yet another embodiment of thepresent disclosure;

FIG. 13 is a view exemplary illustrating a configuration diagram ofLayer 2 for the uplink, which is configured with the WLAN aggregation orthe WLAN interworking in accordance with yet another embodiment of thepresent dislcousre;

FIG. 14 is a view for explaining operation of a terminal, according toan embodiment of the present disclosure;

FIG. 15 is a view for explaining the operation of a base station,according to another embodiment of the present disclosure;

FIG. 16 is a view exemplary illustrating a data transmission path byusing an E-UTRAN carrier and a WLAN carrier in accordance with at leastone embodiment of the present disclosure;

FIG. 17 is a view exemplary illustrating a data transmission path byusing an E-UTRAN carrier and a WLAN carrier in accordance with anotherembodiment of the present disclosure;

FIG. 18 is a view exemplary illustrating a data transmission path byusing an E-UTRAN carrier and a WLAN carrier in accordance with stillanother embodiment of the present disclosure;

FIG. 19 is a view exemplary illustrating a data transmission path byusing an E-UTRAN carrier and a WLAN carrier in accordance with yetanother embodiment of the present disclosure;

FIG. 20 is a view for explaining operation of a terminal, according toan embodiment of the present disclosure;

FIG. 21 is a view exemplary illustrating a user plane protocol structurefor the transmission of user plane data, according to at least oneembodiment of the present disclosure;

FIG. 22 is a view exemplary illustrating a user plane protocol structurefor the transmission of user plane data, according to another embodimentof the present disclosure;

FIG. 23 is a view exemplary illustrating a user plane protocol structurefor the transmission of user plane data, according to still anotherembodiment of the present disclosure;

FIG. 24 is a view for explaining operation of a base station, accordingto an embodiment of the present disclosure;

FIG. 25 is a view illustrating a configuration of a terminal, accordingto an embodiment of the present disclosure; and

FIG. 26 is a view illustrating a configuration of a base station,according to another embodiment of the present disclosure.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, some embodiments of the present disclosure will bedescribed in detail through illustrative drawings. With regard toreference numerals for elements of each drawing, it should be noted thatthe same element will bear the same reference numeral even when it isshown in other drawings. Further, in the following description of thepresent disclosure, the detailed description of related well-knownconfigurations or functions will be omitted if it is determined toobscure the subject matter of the present disclosure.

In the present specification, a machine type communication (MTC)terminal may refer to a terminal that supports a low cost (or lowcomplexity), or the MTC may refer to a terminal that supports coverageenhancement. In the present specification, an MTC terminal may refer toa terminal that supports a low cost (or low complexity) and coverageenhancement. Alternatively, in the present specification, an MTCterminal may refer to a terminal that is defined as a specific categoryto support a low cost (or low complexity) and/or coverage enhancement.

A wireless communication system is widely deployed to provide variouscommunication services, such as voice or packet data, in the presentdisclosure. The wireless communication system includes user equipment(UE) and a base station (BS or eNB). In the present disclosure, the userequipment has a comprehensive concept to refer to a terminal in wirelesscommunication, and it should be interpreted as a concept encompassing amobile station (MS), a user terminal (UT), a subscriber station (SS),and a wireless device in GSM, as well as user equipment in WCDMA, LTE,HSPA, or the like.

A base station or a cell generally refers to a station to communicatewith the user equipment, and may be referred to as another name, such asNode-B, evolved Node-B (eNB), a sector, a site, a base transceiversystem (BTS), an access point, a relay node, a remote radio head (RRH),a radio unit (RU), a small cell, or the like.

That is, a base station or a cell should be interpreted to encompass apartial area or function that is covered by a base station controller(BSC) in CDMA, Node-B in WCDMA, or eNB or a sector (site) in LTE, andhas a meaning that encompasses a variety of coverage areas, such as amega-cell, a macro-cell, a micro-cell, a pico-cell, a femto-cell, arelay node, RRH, RU, small cell communication ranges, or the like.

The various cells described above have a base station for controllingeach cell, and the base station may be interpreted in two senses. i) Thebase station may indicate a device itself that provides a mega-cell, amacro-cell, a micro-cell, a pico-cell, a femto-cell, or a small cell inrelation to the wireless area, or ii) the base station may indicate thewireless area itself. The same entity that controls the devices forproviding a predetermined wireless area in i) or all devices thatinteract with each other to cooperatively configure the wireless areamay be indicated as a base station. The base station may include eNB,RRH, an antenna, RU, LPN, a point, a transmission/reception point, atransmission point, or a reception point depending on the configurationmethod of the wireless area. The base station may be indicated as awireless area itself in which signals are transmitted and received interms of user equipment or from a position of a nearby base station.

Therefore, a mega-cell, a macro-cell, a micro-cell, a pico-cell, afemto-cell, a small cell, RRH, an antenna, RU, LPN (Low Power Node), apoint, eNB, a transmission/reception point, a transmission point, and areception point may be collectively referred to as a base station.

In the present specification, the user equipment and the base stationwill be used to have a comprehensive meaning to indicate two maintransmission and reception entities that are used to implement thetechnology or technical concept described in the present specification,and are not limited to specific terms or words. The user equipment andthe base station will be used to have a comprehensive meaning toindicate two (uplink and downlink) main transmission and receptionentities that are used to implement the technology or technical conceptdescribed in the present specification, and are not limited to specificterms or words. Here, the uplink (UL) refers to a scheme fortransmitting and receiving data to and from the base station by the userequipment, and the downlink (DL) refers to a scheme for transmitting andreceiving data to and from the user equipment by the base station.

Multiple access techniques applied to the wireless communication systemare not limited. Various multiple access techniques may be used, such ascode division multiple access (CDMA), time division multiple access(TDMA), frequency division multiple access (FDMA), orthogonal frequencydivision multiple access (OFDMA), OFDM-FDMA, OFDM-TDMA, OFDM-CDMA, orthe like. One embodiment of the present disclosure may be applied to theresource allocation in asynchronous wireless communication schemes thatevolve to LTE and LTE-Advanced through GSM, WCDMA, and HSPA, and insynchronous wireless communication schemes that evolve to CDMA,CDMA-2000, and UMB. The present disclosure should not be construed to belimited or restricted to a specific wireless communication scheme, andshould be construed to include all the technical fields to which thespirit of the invention can be applied.

The uplink transmission and downlink transmission may use a timedivision duplex (TDD) scheme that transmits data at different times, ormay use a frequency division duplex (FDD) scheme that transmits datawith different frequencies.

In addition, in the system, such as LTE, LTE-Advanced, or the like, theuplink and downlink are configured for a standard based on a singlecarrier wave or a pair of carrier waves. The uplink and downlinktransmit control information through a control channel, such as aphysical downlink control channel (PDCCH), a physical control formatindicator channel (PCFICH), a physical hybrid ARQ indicator channel(PHICH), a physical uplink control channel (PUCCH), an enhanced physicaldownlink control channel (EPDCCH), or the like, and transmit data byconfiguring a data channel, such as a physical downlink shared channel(PDSCH), a physical uplink shared channel (PUSCH), or the like.

Meanwhile, the control information may also be transmitted by usingEPDCCH (enhanced PDCCH or extended PDCCH).

In the present specification, the cell may refer to: coverage of signalstransmitted from a transmission point or transmission/reception point; acomponent carrier that has a coverage of signals transmitted from atransmission point or transmission/reception point; or a transmissionpoint or transmission/reception point itself.

A wireless communication system to which the embodiments are applied maybe a coordinated multi-point transmission/reception system (CoMP system)that transmits signals in cooperation with two or moretransmission/reception points, a coordinated multi-antenna transmissionsystem, or a coordinated multi-cell transmission system. The CoMP systemmay include two or more multi-transmission/reception points andterminals.

The multi-transmission/reception point may be a base station or amacro-cell (hereinafter, referred to as ‘eNB’) and one or more RRHs thatare wiredly controlled while being connected to the eNB through an opticcable or optical fiber, and have a high transmission power or have a lowtransmission power in the macro-cell area.

Hereinafter, the downlink will refer to communication or a communicationpath from a multi-transmission/reception point to a terminal, and theuplink will refer to communication or a communication path from aterminal to a multi-transmission/reception point. In the downlink, atransmitter may be a part of the multi-transmission/reception point, anda receiver may be a part of the terminal. In the uplink, a transmittermay be a part of the terminal, and a receiver may be a part of themulti-transmission/reception point.

Hereinafter, the operation in which a signal is transmitted or receivedthrough a channel, such as PUCCH, PUSCH, PDCCH, EPDCCH, or PDSCH, willalso be expressed as “PUCCH, PUSCH, PDCCH, EPDCCH, or PDSCH istransmitted or received”.

In addition, the expression “PDCCH is transmitted or received or asignal is transmitted or received through PDCCH” may be used as ameaning that includes “EPDCCH is transmitted or received or a signal istransmitted or received through EPDCCH”.

That is, a physical downlink control channel to be described below isused to refer to PDCCH, EPDCCH, or both of them.

In addition, for the convenience of explanation, the EPDCCH that is anembodiment of the present disclosure may be applied to the descriptionthat is made of the PDCCH, and the EPDCCH as an embodiment of thepresent disclosure may be applied to the description that is made of theEPDCCH.

Meanwhile, the upper layer signaling described below includes an RRCsignaling that transmits RRC information including RRC parameters.

The eNB performs a downlink transmission to the terminals. The eNB maytransmit a physical downlink shared channel (PDSCH) that is a mainphysical channel for a unicast transmission, and may transmit a physicaldownlink control channel (PDCCH) for transmitting downlink controlinformation, such as scheduling necessary for the reception of thePDSCH, and scheduling approval information for the transmission in anuplink data channel {for example, a physical uplink shared channel(PUSCH)}. Hereinafter, the operation in which a signal is transmitted orreceived through each channel will be expressed such that thecorresponding channel is transmitted or received.

In the typical 3GPP Release 12, there was a discussion about technologyof 3GPP/WLAN interworking. The 3GPP/WLAN interworking technologyprovides a RAN assisted WLAN interworking function. The E-UTRAN canassist with the terminal-based bi-directional traffic steering betweenthe E-UTRAN and the WLAN with respect to the terminals in the state ofRRC_IDLE and RRC_CONNECTED.

The E-UTRAN provides assistance parameters to the terminal through abroadcast signaling or dedicated RRC signaling. RAN assistanceparameters may include at least one of an E-UTRAN signal intensitythreshold value, a WLAN channel usage threshold value, a WLAN backhauldata rate threshold value, a WLAN signal strength, or an offloadpreference indicator. In addition, the E-UTRAN may provide a list ofWLAN identifiers to the terminal through the broadcast signaling.

The terminal uses the RAN assistance parameters for evaluating accessnetwork selection and traffic steering rules. When the access networkselection and traffic steering rules are fulfilled, the terminal mayindicate the same in an access stratum (AS) upper layer.

When the terminal applies the access network selection and trafficsteering rules, the terminal makes a traffic control in an APNgranularity between the E-UTRAN and the WLAN. As described above, theRAN assisted WLAN interworking function provides only a method in whichthe E-UTRAN and the WLAN are built to stand alone and perform aninterwork function.

However, according to the interworking function described above, sincethe E-UTRAN and the WLAN are built to stand alone and interwork witheach other, it is impossible for the base station to tightly control thewireless resources in consideration of the wireless state or mobility ofthe terminal. Therefore, there is a growing need for a technology thatconsiders tighter integration in the RAN level than the Release 12 RANassisted WLAN interworking function. That is, there is a problem inwhich the terminal cannot use an E-UTRAN carrier and a WLAN carrier atthe same time by adding the WLAN carrier to the E-UTRAN as a carrier inthe RAN level by means of the E-UTRAN in consideration of the wirelessstate or mobility of the terminal in the transmission of specific userplane data. In addition, the terminal cannot effectively select theE-UTRAN carrier and the WLAN carrier for usage in consideration of thewireless state, mobility, or power consumption. The WLAN carrierdescribed above refers to a wireless resource of the WLAN, and may meana WLAN wireless link, a WLAN radio frequency, a WLAN wireless resource,or a WLAN wireless network. However, for the convenience ofunderstanding, a WLAN wireless link, a WLAN radio frequency, a WLANwireless resource, or a WLAN wireless network will be expressed as aWLAN carrier hereinafter. Meanwhile, the typical carrier that is usedfor the data transmission and reception between the terminal and thebase station will be expressed as an LTE carrier, an E-UTRAN carrier, ora base station carrier.

In addition, an RLC layer or a PDCP layer below means a logical layerthat performs a function thereof, and may be implemented in the terminaland the base station. In addition, conceptual entities for performingthe RLC layer and the PDCP layer will be referred to as an RLC entityand a PDCP entity, respectively. Therefore, the RLC layer and the RLCentity may be interchangeably used as necessary. Likewise, the PDCPlayer and the PDCP entity may be interchangeably used as necessary.

Meanwhile, the terminal may utilize the LTE carrier and the WLAN carrierat the same time. To this end, the terminal may split (orroute)/integrate (or aggregate) a user plane data unit to be transmittedin a layer of L4 or more (for example, an application layer, a sessionlayer, a transmission layer, or a core network upper layer), and may usethe LTE carrier and the WLAN carrier in the execution of datacommunication. However, such methods have no standardized procedure, orit is impossible to quickly add/release the WLAN carrier by effectivelyconsidering the wireless environment of the RAN level and the mobilityof the terminal.

As described above, according to the typical E-UTRAN, it is impossibleto simultaneously use the E-UTRAN carrier and the WLAN carrier by addingthe WLAN carrier as a carrier to the E-UTRAN in the RAN level when theterminal transmits specific user plane data.

In addition, the typical method for using the LTE carrier and the WLANcarrier by splitting/integrating a data unit in an application layer, asession layer, a transmission layer, or a core network has a problem inwhich there is no standardized procedure, or the wireless environment ofthe RAN level, the mobility of the terminal, or the power consumptionthereof cannot be effectively considered.

The present disclosure has been made in order to solve the problemsabove, and the objective of the present disclosure is to provide amethod for enabling the terminal i) to add a WLAN carrier as a carrierin the E-UTRAN to the terminal in the RAN level, and ii) to effectivelyselect the E-UTRAN carrier or the WLAN carrier with respect to thedownlink and uplink in consideration of the wireless environment, themobility, or the power consumption to then transmit the user plane datawhen the terminal transmits specific user plane data.

The present disclosure may be provided from the scenario in which a basestation (eNode-B) and a WLAN termination are co-located. The presentdisclosure may also be provided from the scenario in which a basestation (eNode-B) and a WLAN termination are not co-located. In thescenario in which a base station (eNode-B) and a WLAN termination arenot co-located, the base station and the WLAN termination may beconnected through a non-ideal backhaul, a near-ideal backhaul, or anideal backhaul.

The WLAN termination (WT) refers to a logical WLAN network node in thepresent specification. For example, the WT may be a WLAN access point(AP) or a WLAN access controller (AC). The WLAN termination may be thesame WLAN network node as an existing WLAN termination or an existingWLAN AC, or the WLAN termination may be a WLAN network node thatincludes an additional function for the WLAN aggregation transmission inaddition to the existing WLAN termination or the existing WLAN AC. TheWLAN termination may be implemented as a standalone entity, or the WLANtermination may be implemented as a functional entity that is includedin another entity.

For the terminal to add a WLAN carrier as a carrier of the E-UTRAN tothe terminal in the RAN level and to transmit the user plane data byusing the E-UTRAN carrier and the WLAN carrier, a protocol structure forthe same and the operation of each layer should be provided.

The operation of enabling the E-UTRAN to add the WLAN or WLAN carrier asa carrier may logically or conceptually mean that the terminal and thebase station add an additional WLAN carrier or a WLAN PHY/MAC (or L1/L2)transmission function to an existing E-UTRAN cell.

Hereinafter, the structure for transmitting and receiving the downlinkuser plane data and the uplink user plane data of the present disclosurewill be described with reference to the embodiments. Therefore, therespective transmitting and receiving structures may be connected toeach other, or may be applied independently.

<Protocol Provision Structure for Downlink User Plane Data Transmission>

1) Split/Aggregation Structure

Split/Aggregation Structure in RLC Layer

FIG. 1 is a view exemplary illustrating a configuration diagram of Layer2 for the downlink, according to at least one embodiment of the presentdisclosure.

The E-UTRAN may transmit user plane data in an RLC layer by providing asplit/aggregation function as shown in FIG. 1 when transmitting the userplane data by adding a WLAN carrier as a carrier.

The RLC layer provides a function of segmenting and/or concatenating RLCSDUs to allow PDUs to conform to a total size of an RLC PDU that isindicated by a lower layer in a specific transmission opportunitynotified of by the lower layer. In addition, the RLC layer provides anerror correction function through ARQ for the transmission ofacknowledged mode (AM) data.

Since the data transmission (or retransmission) through the WLAN carrieris provided through the WLAN PHY/MAC (or L1/L2) layer, it may not benecessary for the RLC layer to conduct the segmentation and/orconcatenation through the interworking with a WLAN MAC layer that is adifferent standard. However, the RLC layer may provide an HARQreordering function. Thus, when the E-UTRAN wishes to use the WLANcarrier as a carrier in the RLC layer, the data, which is receivedthrough the WLAN carrier different from the E-UTRAN, is reordered byusing the HARQ reordering function (or the reordering of the RLC layer)and then is transmitted in sequence. If the E-UTRAN supports thetransmission by using a plurality of WLANs (or WLAN APs) for anypurpose, such as the improvement of the WLAN coverage, the reorderingmay also be applied to the case where the RLC layer accommodates aplurality of WLANs (or WLAN APs). To this end, the transmitting end ofthe AM RLC entity may not segment and/or concatenate the RLC SDUs thatare to be split and transferred to the WLAN termination 120 when formingthe AMD PDUs from the RLC SDUs.

Alternatively, the transmitting end of the AM RLC entity may perform theretransmission of the RLC data PDUs. The transmitting end of the AM RLCentity may not segment and/or concatenate the RLC PDUs in response to arequest from the WLAN termination 120 or the RLC PDUs to be split andtransferred to the WLAN termination 120 when retransmitting the RLC dataPDUs.

The transmitting end of the AM RLC entity may include a related RLCheader in the RLC data PDU when forming the AMD PDUs from the RLC SDUsor when retransmitting the RLC data PDUs (segments).

As another method, it may be efficient for the RLC layer to segmentand/or concatenate the data to have a constant size to use the WLANcarrier when transmitting the data through the WLAN carrier. Therefore,the RLC layer may perform the same segmenting and/or concatenatingfunction as the typical RLC operation.

Meanwhile, as described above, for the E-UTRAN to add the WLAN carrieras a carrier and to transmit the downlink user data traffic by using orselecting the LTE carrier and the WLAN carrier, an aggregation entityfor aggregation and interworking between the base station and the WLANtermination, an interworking entity or a logical entity for aninterworking function or the LTE-WLAN aggregation may be required. Inthe present specification, such a logical entity will be expressed as anaggregation entity.

The aggregation entity may be a standalone entity or a functional orlogical entity of another network entity. For example, when the basestation and the WLAN termination are co-located to be provided as anintegrated device, the aggregation entity may be a functional entityincluded in the integrated device. The aggregation entity may executefunctions of: creating a tunnel (for example, a GTP tunnel or an IPSECtunnel) necessary for transmitting data between the base station and theterminal through the WLAN carrier; and transmitting data between thebase station and the terminal {between the entity of Layer 2 (forexample, a PDCP entity) of the base station and the entity of Layer 2 ofthe terminal} through the WLAN carrier. As another example, theaggregation entity may be a functional entity that is included in theWLAN termination when the base station and the WLAN termination are notco-located.

In the RLC layer split/aggregation or interlocking structure, theaggregation entity may receive RLC PDUs from the RLC entity of the basestation. Alternatively, the aggregation entity may make a request to theRLC entity of the base station for the RLC PDUs and may receive thesame.

In the RLC layer split/aggregation or interlocking structure, theaggregation entity may transmit the received RLC PDUs to the terminalthrough the WLAN carrier. Alternatively, in the RLC layersplit/aggregation or interlocking structure, the aggregation entity maytransmit the received RLC PDUs to the terminal by using a WLAN L1/L2protocol. Alternatively, in the RLC layer split/aggregation orinterlocking structure, the aggregation entity may transmit the receivedRLC PDUs to the terminal through the WLAN termination (or the WLANcarrier) by using IP communication.

In the RLC layer split/aggregation or interlocking structure, theterminal may transfer the RLC PDUs that are received through the WLANcarrier to the corresponding RLC entity in the terminal. Alternatively,the terminal may transfer the RLC PDUs received by using the WLAN L1/L2protocol in the terminal to the corresponding RLC entity in theterminal.

Meanwhile, in the PDCP layer split/aggregation or interlockingstructure, the aggregation entity may receive PDCP data (for example,PDCP SDUs or PDUs) from the PDCP entity of the base station.Alternatively, the aggregation entity may make a request to the PDCPentity of the base station for the PDCP data (for example, PDCP SDUs orPDCP PDUs), and may receive the PDCP data.

In the PDCP layer split/aggregation or interlocking structure, theaggregation entity may transmit the received PDCP SDUs/PDUs to theterminal through a WLAN wireless link. Alternatively, in the PDCP layersplit/aggregation or interlocking structure, the aggregation entity maytransmit the received PDCP SDUs/PDUs to the terminal by using a WLANL1/L2 protocol. Alternatively, in the PDCP layer split/aggregation orinterlocking structure, the aggregation entity may transmit the receivedPDCP SDUs/PDUs to the terminal through the WLAN termination (or the WLANcarrier) by using IP communication.

In the PDCP layer split/aggregation or interlocking structure, theterminal may receive the PDCP SDUs/PDUs through the WLAN carrier andtransfer the PDCP SDUs/PDUs to the corresponding PDCP entity in theterminal. Alternatively, the terminal may receive the PDCP PDUs by usingthe WLAN L1/L2 protocol in the terminal and transfer the received PDCPPDUs to the corresponding PDCP entity in the terminal.

FIG. 2 is a view exemplary illustrating a configuration diagram of Layer2 for the downlink, according to another embodiment of the presentdisclosure.

FIG. 2 shows another configuration diagram of Layer 2 that provides asplit/aggregation function with respect to the user plane data in theRLC layer when the E-UTRAN transmits the user plane data by adding aWLAN carrier as a carrier.

For example, when the aggregation entity is configured as a functionalentity included in the base station 110 as shown in FIG. 2, it may beconfigured to be included in the RLC entity. As another example, whenthe aggregation entity is configured as a functional entity included inthe base station as shown in FIG. 2, it may be configured as a separateentity that is distinct from the RLC entity.

Split/Aggregation Structure in PDCP Layer

FIG. 3 is a view exemplary illustrating a configuration diagram of Layer2 for the downlink in a split structure, according to still anotherembodiment of the present disclosure, and FIG. 4 is a view illustratinga configuration diagram of Layer 2 for the downlink in a splitstructure, according to yet another embodiment of the presentdisclosure.

The E-UTRAN may transmit the user plane data by providing asplit/aggregation function with respect to the user plane data in a PDCPlayer as shown in FIG. 3 and FIG. 4 when transmitting the user planedata by adding a WLAN carrier as a carrier.

For example, when the aggregation entity is configured as a functionalentity included in the base station 110 as shown in FIG. 4, it may beconfigured to be included in the PDCP entity. For example, theaggregation entity may be configured to be included in the PDCP entity,after a split/routing step of the PDCP PDUs, before a step of performingsequence numbering for the PDCP SDUs, or after a step of sequencenumbering for the PDCP SDUs. As another example, when the aggregationentity is configured as a functional entity included in the base station110 as shown in FIG. 4, it may be configured as a separate entitydistinct from the PDCP entity in a lower layer of the PDCP entity. Asanother example, when the aggregation entity is configured as afunctional entity included in the base station 110, it may be configuredas a separate entity distinct from the PDCP entity in an upper layer ofthe PDCP entity.

The PDCP layer provides a header compression and ciphering function forthe user plane data. In addition, when simultaneously using the E-UTRANcarrier and the WLAN carrier, data may be received in sequence by usinga PDCP reordering function for providing the Release 12 dualconnectivity. Alternatively, if the E-UTRAN supports the transmission byusing a plurality of WLANs (or WLAN terminations) for any purpose, suchas the improvement of the WLAN coverage, data may be received insequence by using a PDCP reordering function for providing the Release12 dual connectivity.

In addition, it is possible to reduce the overhead according to an RLCfunction process and the addition of a header, compared to thesplit/aggregation method through the RLC layer. However, an indicationon a successful delivery of the PDCP PDUs may be required from a lowentity for a data transmission procedure of the PDCP entity. To addressthis, the aggregation entity or the PDCP entity itself may receiveindication information on a successful delivery of the PDCP PDUs. Forexample, a periodic or aperiodic status report or an acknowledgementtransmission operation may be performed.

2) Interworking (or WLAN-Dedicated Bearer) Structure

When the E-UTRAN transmits user plane data by using thesplit/aggregation structure as shown in FIG. 1 to FIG. 4 and whentransmitting the user plane data by adding a WLAN carrier as a carrier,the terminal should perform the reordering in the RLC layer or PDCPlayer in order to receive the downlink data in sequence. The WLAN may:i) have a smaller coverage than the E-UTRAN network; ii) provide a slowstatus monitoring with respect to the wireless link; or iii) not managewireless resources by the network in order to thereby limit theperformance by a significantly increased delay during the reordering.For example, the RLC entity or PDCP entity that performs a windowoperation may cause the window stalling. Alternatively, the datatransmission through the split/aggregation may require an additionalbuffer capacity of the terminal, or the data transmission may causepower consumption thereof for other reasons.

In order to overcome the problems above, in accordance with at least oneembodiment, a method is provided for enabling the E-UTRAN to transmitthe user plane data only through a WLAN carrier when transmitting theuser plane data by adding the WLAN carrier as a carrier. Hereinafter,such a method and an associated interlocking structure according to atleast one embodiment will be described.

RLC Layer Interworking WLAN-Dedicated Bearer Structure

FIG. 5 is a view exemplary illustrating a configuration diagram of Layer2 for the downlink in an interworking structure, according to at leastone embodiment of the present disclosure.

The E-UTRAN may transmit user plane data in the RLC layer by providingan interworking function with respect to the user plane data as shown inFIG. 5 when transmitting the user plane data by adding a WLAN carrier asa carrier.

As described above, the RLC layer provides a function of segmentingand/or concatenating RLC SDUs in order to adjust the PDUs within a totalsize of the RLC PDU that is indicated by a lower layer in a specifictransmission opportunity notified of by the lower layer. The RLC layerprovides an error correction function through ARQ for the transmissionof acknowledged mode (AM) data.

As described above, since the data transmission through a WLAN carrieris provided through the WLAN PHY/MAC (or L1/L2) layer, it may not benecessary for the RLC layer to perform the segmentation and/orconcatenation for the interworking with a WLAN MAC layer that is adifferent standard. However, the RLC layer may provide an errorcorrection function through ARQ for the transmission of acknowledgedmode (AM) data. An acknowledgement on a successful delivery through theWLAN may be received according to the same. If the E-UTRAN supports thetransmission by using a plurality of WLANs (or WLAN APs) for anypurpose, such as the improvement of the WLAN coverage, the RLC layer mayreorder the data that is received through different WLAN APs by using anHARQ reordering function (or the reordering of the RLC layer) to thentransmit the data in sequence. To this end, a transmitting end of the AMRLC entity may not segment and/or concatenate the RLC SDUs to be splitand transferred to the WLAN termination when forming the AMD PDUs fromthe RLC SDUs.

Alternatively, the transmitting end of the AM RLC entity may perform theretransmission of the RLC data PDUs. The transmitting end of the AM RLCentity may not segment and/or concatenate the RLC PDUs in response to arequest from the WLAN termination or the RLC PDUs to be split andtransferred to the WLAN termination when retransmitting the RLC dataPDUs.

The transmitting end of the AM RLC entity may include a related RLCheader in the RLC data PDU when forming the AMD PDUs from the RLC SDUsor when retransmitting the RLC data PDUs (segments).

As another method, it may be efficient for the RLC layer to segmentand/or concatenate the data to have a constant size to use a WLANcarrier when transmitting the data through the WLAN carrier. Therefore,the RLC layer may perform the same segmenting and/or concatenatingfunction as the typical operation of the RLC.

FIG. 6 is a view exemplary illustrating a configuration diagram of Layer2 for the downlink in an interworking structure, according to anotherembodiment of the present disclosure.

FIG. 6 shows another exemplary configuration diagram of Layer 2 forproviding an interworking function with respect to the user plane datain the RLC layer. For example, when the aggregation entity is configuredas a functional entity included in the base station 110 as shown in FIG.6, it may be configured to be included in the RLC entity. As anotherexample, when the aggregation entity is configured as a functionalentity included in the base station 110 as shown in FIG. 6, it may beconfigured as a separate entity from the RLC entity.

PDCP Layer Interworking WLAN-Dedicated Bearer Structure

FIG. 7 is a view exemplary illustrating a configuration diagram of Layer2 for downlink in an interworking structure, according to still anotherembodiment of the present disclosure.

The E-UTRAN may transmit user plane data by providing an interworkingfunction with respect to the user plane data in the PDCP layer as shownin FIG. 7 when transmitting the user plane data by adding a WLAN carrieras a carrier.

FIG. 8 is a view exemplary illustrating a configuration diagram of Layer2 for downlink in an interworking structure, according to yet anotherembodiment of the present disclosure.

The E-UTRAN may transmit user plane data by providing an interworkingfunction with respect to the user plane data in the PDCP layer as shownin FIG. 8 when transmitting the user plane data by adding a WLAN carrieras a carrier.

For example, when the aggregation entity is configured as a functionalentity included in the base station 110 as shown in FIG. 8, it may beconfigured to be included in the PDCP entity. For example, theaggregation entity may be configured by adding aninterworking/switching/routing step of the PDCP PDUs in the PDCP entityor by adding an interworking/switching/routing step of the PDCP SDUsprior to a step of performing the sequence numbering with respect to thePDCP SDUs. Alternatively, the aggregation entity may be configured byadding the same after the step of performing the sequence numbering withrespect to the PDCP SDUs in the PDCP entity. As another example, whenthe aggregation entity is configured as a functional entity included inthe base station 110 as shown in FIG. 8, it may be configured as aseparate entity distinct from the PDCP entity in a lower layer of thePDCP entity. As another example, when the aggregation entity isconfigured as a functional entity included in the base station 110, itmay be configured as a separate entity distinct from the PDCP entity inan upper layer of the PDCP entity.

As described above, the PDCP layer provides a header compression andciphering function with respect to the user plane data. If the E-UTRANsupports the transmission by using a plurality of WLANs (or WLAN APs)for any purpose, such as the improvement of the WLAN coverage, the datamay be received in sequence by using a PDCP reordering function forproviding the Release 12 dual connectivity. Therefore, it is possible toreduce the overhead according to an RLC function process and theaddition of a header, compared to the interworking method through theRLC layer. However, an indication on a successful delivery of the PDCPPDUs may be required from a low entity for a data transmission procedureof the PDCP entity. To address this, the aggregation entity or the PDCPentity itself may receive indication information on a successfuldelivery of the PDCP PDUs. For example, a periodic or aperiodic statusreport or an acknowledgement transmission operation may be received.

Until now, an exemplary structure according to the split or interworkingstructure of the base station and the WLAN termination for thetransmission of the downlink user plane data has been described withreference to the drawings. Hereinafter, a structure of the terminal fortransmitting the uplink user plane data according to the split orinterlocking structure will be described with reference to the drawings.

<Protocol Provision Structure for Uplink User Plane Data Transmission>

Hereinafter, the description will be made of a protocol provisionstructure for transmitting the uplink user plane data and operation of aterminal for transmitting uplink user plane data and receiving downlinkuser plane data.

The base station may transmit downlink user plane data by using thesplit/aggregation structure as shown in FIG. 1, to FIG. 4 when theE-UTRAN transmits the user plane data by adding a WLAN carrier as acarrier. Alternatively, the base station may transmit downlink userplane data by using the interworking structure (or the dedicated bearerstructure) as shown in FIG. 5 to FIG. 8. The transmission of the uplinkuser plane data may be provided in various manners in each case, whichwill be described in more detail below.

1) Uplink Data Transmission Structure Using Base Station Wireless Link

When the E-UTRAN transmits the user plane data by adding a WLAN carrieras a carrier, and when transmitting the downlink user plane dataaccording to each structure of FIG. 1 to FIG. 8, the transmission of theuplink user plane data with respect to the corresponding specificbearer(s) may be performed by using a base station wireless link or byconfiguring and using a base station-dedicated bearer. Alternatively,the transmission of the uplink user plane data for the correspondingspecific bearer(s) may be performed by using a base station carrier orby configuring and using only a base station-dedicated bearer.

FIG. 9 is a view exemplary illustrating a configuration diagram of Layer2 for the uplink, which is configured with the WLAN aggregation or theWLAN interworking in accordance with at least one embodiment.

Referring to FIG. 9, the terminal 900 may transmit the uplink user planedata through the base station when the E-UTRAN transmits the user planedata by adding a WLAN carrier as a carrier. Alternatively, the terminalmay transmit the uplink user plane data only through the base station.

That is, even when the terminal 900 is configured with the WLANaggregation or the interworking to receive the downlink data, the uplinkuser plane data may be transmitted by using the typical uplinktransmission procedure with respect to the base station. For example, byutilizing the typical MAC procedures, such as a logical channel priority(LCP) procedure, a buffer status report (BSR) procedure, or the like, anadditional process of the terminal or the provision of functions are notrequired. In addition, the enhanced mobility performance may be providedby transmitting the uplink data through the base station that has awider coverage than the WLAN.

2) Uplink Data Transmission Structure Using WLAN Carrier

When the E-UTRAN transmits the user plane data by adding a WLAN carrieras a carrier, and when transmitting the downlink user plane dataaccording to each structure of FIG. 1 to FIG. 8, the transmission of theuplink user plane data with respect to the corresponding specificbearer(s) may be performed by using a WLAN carrier or by using aWLAN-dedicated bearer. Alternatively, the transmission of the uplinkuser plane data with respect to the corresponding specific bearer(s) maybe performed by using a WLAN carrier or by using only a WLAN-dedicatedbearer.

FIG. 10 is a view exemplary illustrating a configuration diagram ofLayer 2 for the uplink, which is configured with the WLAN aggregation orthe WLAN interworking in accordance with another embodiment of thepresent disclosure.

As shown in FIG. 10, the terminal may configure a WLAN group fortransmitting uplink user plane data through a WLAN carrier, and theterminal may transmit the same through the WLAN, when the E-UTRANtransmits the user plane data by adding a WLAN carrier as a carrier.Alternatively, the terminal may transmit the uplink user plane data onlythrough the WLAN. Here, the WLAN group may be variously expressed as aWLAN wireless link, a WLAN termination, a WLAN termination group, a WLANgroup, or a non-E-UTRAN group. However, for convenience and ease ofunderstanding, the group for mapping radio bearers that delivers theuplink user plane data through the WLAN carrier or the wireless groupfor transmitting the uplink user plane data through the WLAN carrierwill be expressed as a WLAN group in the description.

The WLAN group for transmitting the uplink user plane data through theWLAN may include a related RLC entity and PDCP entity. The WLAN groupfor transmitting the uplink user plane data through the WLAN may beconfigured regardless of the typical MAC layer or MAC entity.

To this end, the terminal may establish the PDCP entities and RLCentities for the bearers that are associated with the WLAN group throughan RRC-dedicated signaling that is received from the base station. Thatis, bearer configuration information received from the base station mayinclude PDCP-CONFIG information and RLC-CONFIG information.Alternatively, the bearer configuration information may includePDCP-CONFIG information and RLC-CONFIG information without associationwith MAC-MainConfig.

After the terminal received the RRC-dedicated signaling, the terminalmay transfer the RLC PDUs to the aggregation entity in the RLC entity ofthe corresponding radio bearer or may transfer the same through theWLAN.

As described above, since the data transmission through the WLAN carrieris provided through the WLAN PHY/MAC (or L1/L2) layer, it may not benecessary for the RLC layer to perform the segmentation and/orconcatenation through the interworking with the WLAN MAC layer that is adifferent standard. However, the RLC layer may provide an errorcorrection function through ARQ for the transmission of acknowledgedmode (AM) data. An acknowledgement on a successful delivery through theWLAN carrier may be received according to the same. If the E-UTRANsupports the transmission by using a plurality of WLANs (or WLANterminations) for any purpose, such as the improvement of the WLANcoverage, the RLC layer may reorder the data that is received throughdifferent WLAN terminations by using an HARQ reordering function (or thereordering of the RLC layer) to then transmit the data in sequence.

The transmitting end of the AM RLC entity may not segment and/orconcatenate the RLC SDUs in response to a request from the WLANtermination or the RLC SDUs to be split and transferred to the WLANtermination when forming the AMD PDUs from the RLC SDUs.

Alternatively, the transmitting end of the AM RLC entity in the terminalmay perform the retransmission of the RLC data PDUs. The transmittingend of the AM RLC entity in the terminal may not segment and/orconcatenate the RLC PDUs in response to a request from the WLANtermination or the RLC PDUs to be split and transferred to the WLANtermination when retransmitting the RLC data PDUs.

The transmitting end of the AM RLC entity in the terminal may include arelated RLC header in the RLC data PDU when forming the AMD PDUs fromthe RLC SDUs or when retransmitting the RLC data PDUs (segments).

As another method, it may be efficient for the RLC layer to segmentand/or concatenate the data to have a constant size to use the WLANcarrier when transmitting the data through the WLAN carrier. Therefore,the RLC layer may perform the same segmenting and/or concatenatingfunction as the typical operation of the RLC. The size information forthe same may be configured in the terminal through an RRCReconfiguration message, or the size information may be internallyconfigured.

The terminal may submit/forward the RLC data PDU to the aggregationentity. Alternatively, the terminal may transmit the RLC data PDUthrough the WLAN carrier. When the terminal submits the RLC data PDU tothe aggregation entity, or when the terminal transmits the RLC data PDUthrough the WLAN carrier, the terminal may include information foridentifying the radio bearer by the aggregation entity of the basestation in the same and transmit the same. That is, the terminal mayinclude, in the uplink user plane data, information that allows the basestation to transfer the RLC PDUs received through the WLAN carrier tothe RLC entity in the base station, and may transmit the same.

For example, the terminal may send, together with the RLC PDUs,information for mapping the RLC PDUs transmitted by the terminal withthe RLC entity in the base station. Alternatively, the terminal mayattach, to the header information of the RLC PDUs, the information formapping the RLC PDUs transmitted by the terminal with the RLC entity inthe base station, and may transmit the same. Alternatively, the terminalmay add, as new header information (for example, new information in theRLC header or new information in a new header for the payload of the RLCPDUs), information for mapping the RLC PDUs transmitted by the terminalwith the RLC entity in the base station, and may transmit the same.Alternatively, the terminal may include information for mapping the RLCPDUs transmitted by the terminal with the RLC entity of the base stationin a WLAN MAC header, an LLC header, an IP header, a UDP header, a GTPheader, or an IPSEC header between the WLAN termination and theterminal, which includes the RLC PDUs, and may transmit the same.

Meanwhile, preferably, the information for mapping the RLC PDUstransmitted by the terminal with the RLC entity of the base station mayuse the information for identifying the corresponding radio bearer.

For example, a logical channel identifier that has a value of 3 to 10may be used as the information for mapping the RLC PDUs transmitted bythe terminal with the RLC entity of the base station. As anotherexample, eps-BearerIdentity may be used as the information for mappingthe RLC PDUs transmitted by the terminal with the RLC entity of the basestation. As another example, dRB-Identity may be used as the informationfor mapping the RLC PDUs transmitted by the terminal with the RLC entityof the base station. As another example, as the information for mappingthe RLC PDUs transmitted by the terminal with the RLC entity of the basestation, index information for identifying the corresponding radiobearer may be newly defined and used. Then, the index information foridentifying the radio bearer may be added to DRB configurationinformation (DRB-ToAddMod) in the terminal.

The terminal may establish an aggregation entity in the terminal, whichis peered with the aggregation entity described above. Alternatively,the terminal may establish, in the RLC entity, an aggregation entity inthe terminal, which is peered with the aggregation entity describedabove.

The aggregation entity in the terminal, which is peered with theaggregation entity described above, may receive the RLC PDUs from theRLC entity, and the aggregation entity may associate the same with theinformation (for example, the identification information or tunnelendpoint information) for mapping the RLC PDUs transmitted by theterminal with the RLC entity of the base station. In addition, theterminal may forward the same to the aggregation entity described abovethrough the WLAN carrier, and the terminal may allow the aggregationentity to forward the same to the corresponding RLC entity.

Alternatively, for the base station to map the RLC PDUs to betransmitted through the WLAN carrier with a corresponding RLC entity inthe RLC layer, the terminal may associate the RLC PDUs transmitted bythe terminal with the information (for example, the identificationinformation or tunnel endpoint information) for the mapping with the RLCentity in the base station. In addition, the terminal mayforward/transfer/submit the same to a logical entity (or layer) for thetransmission thereof through the WLAN carrier.

FIG. 11 is a view exemplary illustrating a configuration diagram ofLayer 2 for the uplink, which is configured with the WLAN aggregation orthe WLAN interworking in accordance with yet another embodiment of thepresent disclosure.

As shown in FIG. 11, the terminal may configure a WLAN group fortransmitting the uplink user plane data through a WLAN carrier, and theterminal may transmit the same through the WLAN carrier. Alternatively,the terminal may transmit the same only through a WLAN carrier.

The WLAN group may include a related PDCP entity. The WLAN group may beconfigured regardless of the MAC layer or MAC entity.

To this end, the terminal may establish the PDCP entities for thebearers that are associated with the WLAN group through an RRC-dedicatedsignaling that is received from the base station. That is, thecorresponding bearer configuration information may include PDCP-CONFIGinformation. Alternatively, the corresponding bearer configurationinformation may include PDCP-CONFIG information without association withMAC-MainConfig and RLC-CONFIG information. Alternatively, thecorresponding bearer configuration information may not include theRLC-CONFIG information, and the corresponding bearer configurationinformation may include only the PDCP-CONFIG information withoutassociation with the MAC-MainConfig information.

After the terminal has received the RRC-dedicated signaling, theterminal may transfer the PDCP SDUs or the PDUs to the aggregationentity in the PDCP entity of the corresponding radio bearer.Alternatively, the terminal may transfer the user plane data {that is,the PDCP SDUs (IP packets)} to the base station through a WLAN carrier.

With regard to the bearer that is configured as shown in FIG. 11, whenthe terminal receives the PDCP SDU from an upper layer, the terminal mayexecute at least one of the typical operations {for example, operationsof associating the PDCP SN, performing header compression of the PDCPSDU (if configured), or performing integrity protection and ciphering}of the PDCP layer for the uplink data transmission. Alternatively, whenreceiving the PDCP SDU from an upper layer, the terminal maysubmit/transfer the same to the aggregation entity.

The terminal may submit/transfer the PDCP data (PDCP SDU or PDCP PDU) tothe aggregation entity. Alternatively, the terminal transmits the PDCPSDU/PDU through the WLAN carrier. When submitting the PDCP SDU/PDU tothe aggregation entity, or when transmitting the PDCP SDU/PDU throughthe WLAN carrier, the terminal may include, in the same, information toallow the base station to transfer the PDCP SDUs/PDUs that are receivedthrough the WLAN wireless link to the corresponding PDCP entity in thebase station, and may send the same.

To allow the base station to transfer the PDCP SDUs/PDUs receivedthrough the WLAN carrier to the PDCP entity in the base station, theterminal may send information for mapping the PDCP SDUs/PDUs transmittedby the terminal with the PDCP entity of the base station together withthe PDCP SDUs/PDUs. Alternatively, the terminal may attach, to theheader information of the PDCP SDUs/PDUs, the information for mappingthe PDCP SDUs/PDUs transmitted by the terminal with the PDCP entity inthe base station, and the terminal may transmit the same. Alternatively,the terminal may add, as new header information (for example, newinformation in the PDCP header or new information in a new header forthe payload of the PDCP SDUs/PDUs), information for mapping the PDCPSDUs/PDUs transmitted by the terminal with the PDCP entity in the basestation, and the terminal may transmit the same. Alternatively, theterminal may include information for mapping the PDCP SDUs/PDUstransmitted by the terminal with the PDCP entity of the base station ina WLAN MAC header, an LLC header, an IP header, a UDP (User DatagramProtocol) header, a GTP (GPRS Tunneling Protocol) header, or an IPSEC(Internet Protocol Security Protocol) header between the WLANtermination and the terminal, which includes the PDCP SDUs/PDUs, and maytransmit the same.

Preferably, the information for mapping the PDCP PDUs transmitted by theterminal with the PDCP entity in the base station may use theinformation for identifying the corresponding radio bearer.

For example, a logical channel identifier that has a value of 3 to 10may be used as the information for mapping the PDCP PDUs transmitted bythe terminal with the PDCP entity in the base station. As anotherexample, eps-BearerIdentity may be used as the information for mappingthe PDCP PDUs transmitted by the terminal with the PDCP entity in thebase station. As another example, dRB-Identity may be used as theinformation for mapping the PDCP PDUs transmitted by the terminal withthe PDCP entity in the base station. As another example, as theinformation for mapping the PDCP PDUs transmitted by the terminal withthe PDCP entity in the base station, index information for identifyingthe corresponding radio bearer may be newly defined and used, and theindex information for identifying the radio bearer may be added to DRBconfiguration information (DRB-ToAddMod) in the terminal to then beconfigured.

The terminal may establish an aggregation entity in the terminal, whichis peered with the aggregation entity described above. Alternatively,the terminal may establish, in the PDCP entity, an aggregation entity ofthe terminal, which is peered with the aggregation entity describedabove.

The aggregation entity in the terminal, which is peered with theaggregation entity described above, may receive the PDCP PDUs from thePDCP entity, and may associate the same with the information (forexample, the identification information or tunnel endpoint information)for mapping the PDCP PDUs transmitted by the terminal with the PDCPentity of the base station. In addition, the terminal may transfer thesame to the aggregation entity described above through the WLAN carrier,and may allow the aggregation entity to transfer the same to thecorresponding PDCP entity.

Alternatively, for the base station to map the PDCP PDUs to betransmitted through the WLAN carrier with a corresponding PDCP entity inthe PDCP layer, the terminal may associate the PDCP PDUs transmitted bythe terminal with the information (for example, the identificationinformation or tunnel endpoint information) for the mapping with thePDCP entity in the base station. In addition, the terminal mayforward/transfer/submit the same to a logical entity (or layer) for thetransmission through the WLAN carrier.

As shown in FIG. 10 and FIG. 11, since the terminal processes the uplinkuser plane data through the WLAN carrier or the WLAN-dedicated bearer inthe situation of WLAN aggregation, the terminal may utilize a nearbyWLAN termination. Therefore, it is possible to reduce the powerconsumption of the terminal. Furthermore, it is possible to reduce theusage of the E-UTRAN wireless resources by offloading the uplink trafficof the base station.

3) Simultaneous Transmission of Link Data Using Base Station Carrier andWLAN Carrier

The terminal may transmit uplink user plane data for specific bearers byusing a base station carrier and a WLAN carrier in the case of using thestructures described in FIG. 1 to FIG. 8 when the E-UTRAN transmits theuser plane data by adding the WLAN carrier as a carrier.

FIG. 12 is a view exemplary illustrating a configuration diagram ofLayer 2 for the uplink, which is configured with the WLAN aggregation orthe WLAN interworking in accordance with still another embodiment, andFIG. 13 is a view exemplary illustrating a configuration diagram ofLayer 2 for the uplink, which is configured with the WLAN aggregation orthe WLAN interworking in accordance with yet another embodiment.

As shown in FIG. 12 or FIG. 13, the terminal may transmit the uplinkuser plane data by using a base station carrier and a WLAN carrier whenthe E-UTRAN transmits the user plane data by adding a WLAN carrier as acarrier.

The RLC entity of FIG. 12 or the PDCP entity of FIG. 13 splits or routesthe uplink data into the base station carrier and the WLAN carrier andtransfer the same.

As shown the FIG. 12 or FIG. 13, the terminal transmits the uplink userplane data through the base station carrier and the WLAN carrier so thatthe terminal is configured with the WLAN aggregation or the WLANinterworking. Therefore, it is possible to improve the uplink datatransmission rate/throughput in the case of receiving the downlink data.In addition, when the WLAN wireless link quality temporarily becomesbad, it is possible to enhance the performance by transmitting orretransmitting the uplink data through the E-UTRAN. However, in the caseof transmitting the uplink user plane data through the base stationcarrier and the WLAN carrier, when the terminal performs a buffer statusreporting procedure for performing the uplink data transmission throughthe MAC of the E-UTRAN, the terminal may make a buffer status report toexceed the actual transmission amount of E-UTRAN because the terminaluses the data available for the transmission of the PDCP entity and thedata available for the transmission of the RLC entity in FIG. 12 or thedata available for the transmission of the PDCP entity in FIG. 13. Inorder to address this, in the case where a base station-dedicated beareror a WLAN-dedicated bearer is configured to be used for the uplink datatransmission or the terminal performs a buffer status reportingprocedure for the uplink data transmission through the MAC of theE-UTRAN, the terminal may report only some (or a constant amount) of thedata available for the transmission of the PDCP entity and the dataavailable for the transmission of the RLC entity in FIG. 12 or some ofthe data available for the transmission of the PDCP entity in FIG. 13.Alternatively, the uplink user plane data transmission may be performedby means of the base station carrier using method or the WLAN carrierusing method.

<Bearer Configuration Information>

The base station may be configured to enable the terminal to transmitthe user plane data by adding a WLAN carrier to a base station carrierby using an upper layer message (for example, an RRC Reconfigurationmessage). Alternatively, the base station may be configured to enable anRRC-connected terminal to transmit the user plane data by adding a WLANcarrier by means of an upper layer message (for example, an RRCreconfiguration message).

For example, the base station may be configured to enable the terminali) to receive the downlink user plane data for a specific radio bearerthrough the interworking structure (or the WLAN-dedicated bearerstructure or the WLAN wireless link using structure) described above andii) to transmit the uplink user plane data through the base stationwireless link using structure (or the base station-dedicated bearerstructure).

For example, in the RLC layer interlocking structure, the downlink RLCdata PDU, as described with reference to FIG. 5 and FIG. 6, may betransmitted from the RLC entity of the base station to the RLC entity ofthe terminal through the WLAN carrier. On the contrary, as describedwith reference to FIG. 9, the uplink RLC data PDU may be transmittedfrom the RLC entity of the terminal to the RLC entity of the basestation through the base station carrier.

An uplink RLC status report with respect to the downlink RLC data PDUmay be transmitted from the RLC entity of the terminal to the RLC entityof the base station through the base station carrier. A downlink RLCstatus report with respect to the uplink RLC data PDU may be transmittedfrom the RLC entity of the base station to the RLC entity of theterminal through the base station carrier.

In this case, if the downlink RLC entity of the terminal does not allowthe transmission through different APs, the reordering function may notbe performed. Alternatively, the RLC SDU may be transmitted to the PDCPentity without performing the reordering function. Alternatively, aT-reordering timer may be set to be zero or a small value.

As another example, in the PDCP layer interworking structure describedabove, the downlink PDCP data PDU, as described in FIG. 7 and FIG. 8,may be transmitted from the PDCP entity of the base station to the PDCPentity of the terminal through WLAN carrier. On the contrary, the uplinkPDCP data PDU, as described in FIG. 9, may be transmitted from the PDCPentity of the terminal to PDCP entity of the base station through thebase station carrier. An acknowledgement on a successful delivery of thePDCP SDUs/PDUs from a low entity may be required for the datatransmission procedure of the PDCP entity. To address this, theaggregation entity or the PDCP entity itself may be configured toreceive indication information on a successful delivery of the PDCPSDUs/PDUs. For example, a periodic or aperiodic status report or anacknowledgement transmission operation may be performed.

To configure this, the information for instructing the terminal toreceive the downlink data through a WLAN carrier (or information foridentifying the type of bearer) may be included in the radio bearerconfiguration information (DRB-ToAddMod) to then be transmitted.Alternatively, in the case of the RLC layer interworking structure (FIG.5 and FIG. 6) described above, the information for instructing theterminal to receive the downlink data through a WLAN carrier (orinformation for identifying the type of bearer) may be included in theRLC configuration information (RLC-CONFIG) and transmitted.Alternatively, in the case of the PDCP layer interworking structure(FIG. 7 and FIG. 8) described above, the information for instructing theterminal to receive the downlink data through a WLAN carrier (orinformation for identifying the type of bearer) may be included in thePDCP configuration information (PDCP-CONFIG) to then be transmitted. Theinformation for instructing the terminal to transmit the uplink datathrough a base station carrier (or information for designating theuplink data path) and the information to configure the content describedabove may be included in the RLC configuration information (RLC-CONFIG)in the case of the radio bearer configuration information (DRB-ToAddMod)or the RLC layer interworking structure described above, or may beincluded in the PDCP configuration information (PDCP-CONFIG) in the caseof the PDCP layer interworking structure described above, and may betransmitted.

Alternatively, the base station may be configured to enable the terminalto receive the downlink user plane data for a specific radio bearerthrough the interworking structure (or the WLAN-dedicated bearerstructure or the WLAN wireless link using structure) described above,and to transmit the uplink user plane data through the WLAN signal linkusing structure (or the WLAN-dedicated bearer structure) describedabove.

For example, in the RLC layer interworking structure described above,the downlink RLC data PDU, as shown in FIG. 5 and FIG. 6, may betransmitted from the RLC entity of the base station to the RLC entity ofthe terminal through a WLAN carrier. The uplink RLC data PDU, as shownin FIG. 10, may be transmitted from the RLC entity of the terminal tothe RLC entity of the base station through a WLAN carrier.

An uplink RLC status report with respect to the downlink RLC data PDUmay be transmitted from the RLC entity of the terminal to the RLC entityof the base station through the WLAN carrier. A downlink RLC statusreport with respect to the uplink RLC data PDU may be transmitted fromthe RLC entity of the base station to the RLC entity of the terminalthrough the WLAN carrier.

In this case, if the downlink RLC entity of the terminal does not allowthe transmission through different APs, the reordering function may notbe performed. Alternatively, the RLC SDU may be transferred to the PDCPentity without performing the reordering function. As another method, aT-reordering timer may be configured to be zero or a small value.

As another example, in the PDCP layer interworking structure describedabove, the downlink PDCP data PDU, as described in FIG. 7 and FIG. 8,may be transmitted from the PDCP entity of the base station to the PDCPentity of the terminal through a WLAN wireless link. The uplink PDCPdata PDU, as described in FIG. 11, may be transmitted from the PDCPentity of the terminal to PDCP entity of the base station through a WLANcarrier. An acknowledgement on a successful delivery of the PDCP PDUsfrom a low entity may be required for the data transmission procedure ofthe PDCP entity. To address this, the aggregation entity or the PDCPentity itself may be configured to receive indication information on asuccessful delivery of the PDCP PDUs. For example, a periodic oraperiodic status report or an acknowledgement transmission operation maybe performed.

To configure this, the information for instructing the terminal totransmit or receive the downlink or uplink data through a WLAN carrier(or information for identifying the downlink/uplink WLAN wireless linkusage or the type of downlink WLAN wireless link using bearer) may beincluded in the radio bearer configuration information (DRB-ToAddMod),and transmitted. Alternatively, in the case of the RLC layerinterworking structure, the information for instructing the terminal totransmit and/or receive the downlink and/or uplink data through a WLANcarrier (or information for identifying the downlink/uplink WLANwireless link usage or the type of downlink WLAN wireless link usingbearer) may be included in the RLC configuration information(RLC-CONFIG) and transmitted. Alternatively, in the case of the PDCPlayer interworking structure, the information for instructing theterminal to transmit and/or receive the downlink and/or uplink datathrough a WLAN carrier (or information for identifying thedownlink/uplink WLAN wireless link usage or the type of downlink WLANwireless link using bearer) may be included in the PDCP configurationinformation (PDCP-CONFIG) and transmitted. Additionally oralternatively, the information for instructing the terminal to transmitthe uplink data through a WLAN carrier (or information for designatingthe uplink data path) and/or the information to configure the contentdescribed above (for example, information to instruct to provide anacknowledgement on a successful delivery of the base station PDCP PDUs)may be included in the RLC configuration information (RLC-CONFIG) in thecase of the radio bearer configuration information (DRB-ToAddMod) or theRLC layer interworking structure described above, or the information maybe included in the PDCP configuration information (PDCP-CONFIG) in thecase of the PDCP layer interworking structure described above. Then, thesame may be transmitted.

Alternatively, the base station may be configured to enable the terminalto receive the downlink user plane data for a specific radio bearerthrough the split/aggregation structure described above and to transmitthe uplink user plane data through the base station wireless link usingstructure (or base station-dedicated bearer structure).

For example, in the RLC layer split/aggregation structure describedabove, the downlink RLC data PDU, as shown in FIGS. 1 and 2, may betransmitted from the RLC entity of the base station to the RLC entity ofthe terminal through a base station wireless link and/or a WLAN wirelesslink. On the contrary, the uplink RLC data PDU, as shown in FIG. 9, maybe transmitted from the RLC entity of the terminal to the RLC entity ofthe base station through a base station carrier.

An uplink RLC status report with respect to the downlink RLC data PDUmay be transmitted from the RLC entity of the terminal to the RLC entityof the base station through the base station carrier. A downlink RLCstatus report with respect to the uplink RLC data PDU may be transmittedfrom the RLC entity of the base station to the RLC entity of theterminal through the base station carrier. Alternatively, a downlink RLCstatus report with respect to the uplink RLC data PDU may be transmittedfrom the RLC entity of the base station to the RLC entity of theterminal through the base station carrier and the WLAN carrier.

As another example, in the PDCP layer split/aggregation structuredescribed above, the downlink PDCP data PDU, as shown in FIG. 3 and FIG.4, may be transmitted from the PDCP entity of the base station to thePDCP entity of the terminal through a base station wireless link and/ora WLAN wireless link. On the contrary, the uplink PDCP data PDU, asshown in FIG. 9, may be transmitted from the PDCP entity of the terminalto the PDCP entity of the base station through a base station carrier.An acknowledgement on a successful delivery of the PDCP PDUs from a lowentity may be required for the data transmission procedure of the PDCPentity. To address this, the aggregation entity or the PDCP entityitself may be configured to receive indication information on asuccessful delivery of the PDCP PDUs. For example, a periodic oraperiodic status report or an acknowledgement transmission operation maybe performed.

To configure this, the information for instructing the terminal toreceive the downlink data through a WLAN carrier (or information foridentifying the type of bearer) may be included in the radio bearerconfiguration information (DRB-ToAddMod) to then be transmitted.Alternatively, in the case of the RLC layer split/aggregation structuredescribed above, the information for instructing the terminal to receivethe downlink data through a base station carrier or a WLAN carrier (orinformation for identifying the type of bearer) may be included in theRLC configuration information (RLC-CONFIG), and the information may betransmitted with the RLC configuration information. Alternatively, inthe case of the PDCP layer split/aggregation structure described above,the information for instructing the terminal to receive the downlinkdata through a base station carrier or a WLAN carrier (or informationfor identifying the type of bearer) may be included in the PDCPconfiguration information (PDCP-CONFIG) and be transmitted. Additionallyor alternatively, the information for instructing the terminal totransmit the uplink data through a base station carrier (or informationfor designating the uplink data path) and/or the information toconfigure the content described above (for example, information toinstruct to provide an acknowledgement on a successful delivery of thebase station PDCP PDUs) may be included in the RLC configurationinformation (RLC-CONFIG) in the case of the radio bearer configurationinformation (DRB-ToAddMod) or the RLC layer split/aggregation structuredescribed above, or the information may be included in the PDCPconfiguration information (PDCP-CONFIG) in the case of the PDCP layersplit/aggregation structure described above. Then, the information maybe transmitted.

Alternatively, the base station may be configured to enable the terminali) to receive the downlink user plane data for a specific radio bearerthrough the split/aggregation structure described above and ii) totransmit the uplink user plane data through the WLAN carrier usingstructure (or the WLAN-dedicated bearer structure) described above.

For example, in the RLC layer split/aggregation structure describedabove, the downlink RLC data PDU, as shown in FIG. 1 and FIG. 2, may betransmitted from the RLC entity of the base station to the RLC entity ofthe terminal through a base station carrier and/or a WLAN carrier. Onthe contrary, the uplink RLC data PDU, as shown in FIG. 10, may betransmitted from the RLC entity of the terminal to the RLC entity of thebase station through a WLAN wireless link/carrier.

An uplink RLC status report with respect to the downlink RLC data PDUmay be transmitted from the RLC entity of the terminal to the RLC entityof the base station through the WLAN carrier. A downlink RLC statusreport with respect to the uplink RLC data PDU may be transmitted fromthe RLC entity of the base station to the RLC entity of the terminalthrough the base station carrier. Alternatively, a downlink RLC statusreport with respect to the uplink RLC data PDU may be transmitted fromthe RLC entity of the base station to the RLC entity of the terminalthrough the base station carrier and the WLAN carrier.

As another example, in the PDCP layer split/aggregation structuredescribed above, the downlink PDCP data PDU, as shown in FIG. 3 and FIG.4, may be transmitted from the PDCP entity of the base station to thePDCP entity of the terminal through a base station carrier and/or a WLANcarrier. On the contrary, the uplink PDCP data PDU may be transmittedfrom the PDCP entity of the terminal to the PDCP entity of the basestation through a WLAN carrier. An acknowledgement on a successfuldelivery of the PDCP PDUs from a low entity may be required for the datatransmission procedure of the PDCP entity. To address this, theaggregation entity or the PDCP entity itself may be configured toreceive indication information on a successful delivery of the PDCPPDUs. For example, a periodic or aperiodic status report or anacknowledge transmission operation may be performed.

To configure this, the information for instructing the terminal toreceive the downlink data through a base station carrier or a WLANcarrier (or information for identifying the type of bearer) may beincluded in the radio bearer configuration information (DRB-ToAddMod),and the same may be transmitted. Alternatively, in the case of the RLClayer split/aggregation structure, the information for instructing theterminal to receive the downlink data through a base station carrierand/or a WLAN carrier (or information for identifying the type ofbearer) may be included in the RLC configuration information(RLC-CONFIG), and the same may be transmitted. Alternatively, in thecase of the PDCP layer split/aggregation structure, the information forinstructing the terminal to receive the downlink data through a basestation carrier and/or a WLAN carrier (or information for identifyingthe type of bearer) may be included in the PDCP configurationinformation (PDCP-CONFIG), and the same may be transmitted. Additionallyor alternatively, the information for instructing the terminal totransmit the uplink data through a WLAN carrier (or information fordesignating the uplink data path) and/or the information to configurethe content described above (for example, information to instruct toprovide an acknowledgement on a successful delivery of the base stationPDCP PDUs) may be included in the RLC configuration information(RLC-CONFIG) in the case of the radio bearer configuration information(DRB-ToAddMod) or the RLC layer split/aggregation structure describedabove, or the same may be included in the PDCP configuration information(PDCP-CONFIG) in the case of the PDCP layer split/aggregation structuredescribed above. After the including, the same may be transmitted.

As described above, the base station may include the information forseparating the transfer path of the downlink user plane data and/or theinformation for separating the transfer path of the uplink user planedata for each radio bearer. That is, the terminal may recognize thereception structure of the downlink user plane data. The terminal mayreceive the downlink user plane data through a corresponding entity andprocess the received downlink user plane data. Alternatively, theterminal may configure a transmission structure of the uplink user planedata and transmit data through the same.

For example, if the base station and the WLAN termination are connectedto each other through a backhaul having a relatively large delay, thebase station may attempt to perform the downlink transmission onlythrough a WLAN carrier. In the case of a large backhaul delay, even ifthe downlink data is transmitted through a split structure thataggregates the base station carrier and the WLAN carrier, the reorderingrequires a lot of processing, thereby degrading the performance. Whenthe WLAN wireless state is changed due to the movement of the terminalduring the attempt at the downlink transmission only through the WLANcarrier, it may cause a delay and a data interruption to process theswitch from the radio bearer (for example, FIG. 5 to FIG. 8) that isconfigured to receive data only through the WLAN carrier into a basestation bearer.

To address this, in the case of configuring the terminal to receive dataonly through the WLAN carrier, the base station may configureinformation to allow the terminal that receives data only through theWLAN carrier to quickly switch to the base station bearer whenconfiguring to receive data only through the WLAN carrier.

For example, the description will be made of a radio bearer that isconfigured to transmit the downlink data only through a WLAN carrier byinterworking with the PDCP entity and is configured to transmit theuplink data only through the base station carrier.

The base station transmits information to configure/add/correct thedownlink data transmission bearer through a WLAN carrier to the terminalthrough an RRC reconfiguration message. The configuration information toconfigure/add/correct the downlink data transmission bearer through aWLAN carrier may include information (for example, tunnel endpointinformation in a GTP tunnel or IPSEC tunnel) to transmit the downlinkdata (PDCP SDUs or PDCP PDUs) to the terminal through a WLAN carrier orinformation by which the terminal separates and transfers the downlinkdata received through a WLAN carrier to the PDCP entity (or theaggregation entity). In addition, the RRC reconfiguration message mayinclude the radio bearer configuration information (DRB-ToAddMod) toconfigure the terminal to transmit the uplink data through the basestation carrier.

When the terminal detects a problem in the WLAN wireless link, theterminal may report the same to the base station. Alternatively, thebase station may directly find the problem of the WLAN wireless link.Thereafter, the base station may operate as follows.

For example, the base station transmits the downlink data through thebase station carrier. That is, the data may be received by using theradio bearer configuration information (DRB-ToAddMod) that is configuredto transmit the uplink data.

As another example, the base station transmits information torelease/correct the downlink data transmission bearer through a WLANcarrier to the terminal through an RRC reconfiguration message. At thistime, the radio bearer configuration information (DRB-ToAddMod) may betransferred through a delta signaling. At this time, the base stationmay instruct the PDCP entity/aggregation entity of the terminal totransfer, to the base station, the PDCP SDUs/PDUs that have beenreceived successfully. The instruction information for the same may beconfigured through the RRC reconfiguration message.

The base station may retransmit the PDCP SDUs or PDCP PDUs based on thesame. In addition, the base station may submit the PDCP SDUs or PDCPPDUs to a low entity based on the same.

As described above, in accordance with at least one embodiment, theterminal is enabled to transmit the user plane data by simultaneouslyusing the E-UTRAN carrier and the WLAN carrier with respect to thedownlink and/or uplink in a unit of radio bearer or by selecting theE-UTRAN carrier or the WLAN carrier when transmitting the user planedata by adding the WLAN carrier to the E-UTRAN carrier.

Hereinafter, the operation of the terminal and the base stationaccording to the embodiments of present disclosure, will be describedagain with reference to the drawings.

FIG. 14 is a flowchart for explaining operation of a terminal, accordingto an embodiment of the present disclosure.

The terminal, according to an embodiment of the present disclosure, mayprocess the user plane data by a method including: receiving additionalconfiguration information to further configure a WLAN carrier that usesan unlicensed frequency band; receiving downlink user plane data througha WLAN carrier or a base station carrier that uses a licensed frequencyband according to the additional configuration information; andtransmitting included uplink user plane data through the WLAN carrier orthe base station carrier according to the additional configurationinformation.

Referring to FIG. 14, the terminal may execute receiving additionalconfiguration information to further configure a WLAN carrier that usesan unlicensed frequency band (S1410). The additional configurationinformation may include information for identifying the transfer path ofthe downlink user plane data or information for identifying the transferpath of the uplink user plane data for each radio bearer. That is, asdescribed above, the additional configuration information may includeinformation for configuring a reception structure of the downlink userplane data and a transmission structure of the uplink user plane data.For example, it may include information to configure the PDCP entity,the RLC entity, or the aggregation entity.

The terminal may perform receiving the downlink user plane data througha WLAN carrier or a base station carrier that uses a licensed frequencyband according to the additional configuration information (S1420). Theterminal may execute transmitting included uplink user plane datathrough the WLAN carrier or the base station carrier according to theadditional configuration information (S1430).

For example, the downlink user plane data may be received through theWLAN carrier by an interworking function in the PDCP (Packet DataConvergence Protocol) entity of the base station, and the uplink userplane data may be transmitted only through the base station carrier.Alternatively, the downlink user plane data may be received through theWLAN carrier by an interworking function in the PDCP (Packet DataConvergence Protocol) entity of the base station, and the uplink userplane data may be transmitted only through the WLAN carrier.Alternatively, the downlink user plane data may be received through theWLAN carrier and the base station carrier by a split function in thePDCP (Packet Data Convergence Protocol) entity of the base station, andthe uplink user plane data may be transmitted only through the basestation carrier. Alternatively, the downlink user plane data may bereceived through the structure of each embodiment described withreference to FIG. 1 to FIG. 8. In addition, the uplink user plane datamay be transmitted through the structure of each embodiment describedwith reference to FIG. 9 to FIG. 13.

Meanwhile, when the terminal transmits the uplink user plane data onlythrough the WLAN carrier, the terminal may add information foridentifying the radio bearer in the aggregation entity to the uplinkuser plane data, and may transmit the same.

Furthermore, the terminal may receive and transmit the downlink userplane data and the uplink user plane data by a combination of thedownlink structure and the uplink structure described above.

FIG. 15 is a flowchart for explaining operation of a base station,according to an embodiment of the present disclosure.

The base station, according to an embodiment of the present disclosure,may process the user plane data by a method including: creating andtransmitting additional configuration information to further configure aWLAN carrier that uses an unlicensed frequency band; transmittingdownlink user plane data through a WLAN carrier or a base stationcarrier that uses a licensed frequency band according to the additionalconfiguration information; and receiving uplink user plane data throughthe WLAN carrier or the base station carrier according to the additionalconfiguration information.

Referring to FIG. 15, the base station may execute creating andtransmitting additional configuration information to further configure aWLAN carrier that uses an unlicensed frequency band (S1510). Theadditional configuration information may include information foridentifying the transfer path of the downlink user plane data orinformation for identifying the transfer path of the uplink user planedata for each radio bearer. That is, as described above, the additionalconfiguration information may include information for configuring atransmission structure of the downlink user plane data and a receptionstructure of the uplink user plane data. For example, it may includeinformation to configure the PDCP entity, the RLC entity, or theaggregation entity.

The base station may execute transmitting downlink user plane datathrough a WLAN carrier or a base station carrier that uses a licensedfrequency band according to the additional configuration information(S1520). The base station may execute receiving uplink user plane datathrough the WLAN carrier or the base station carrier according to theadditional configuration information (S1530).

For example, the downlink user plane data may be transmitted through theWLAN carrier by an interworking function in the PDCP (Packet DataConvergence Protocol) entity of the base station, and the uplink userplane data may be received only through the base station carrier.Alternatively, the downlink user plane data may be transmitted throughthe WLAN carrier by an interworking function in the PDCP (Packet DataConvergence Protocol) entity of the base station, and the uplink userplane data may be received only through the WLAN carrier. Alternatively,the downlink user plane data may be transmitted through the WLAN carrierand the base station carrier by a split function in the PDCP (PacketData Convergence Protocol) entity of the base station, and the uplinkuser plane data may be received only through the base station carrier.Alternatively, the downlink user plane data may be transmitted throughthe structure of each embodiment described with reference to FIG. 1 toFIG. 8. In addition, the uplink user plane data may be received throughthe structure of each embodiment described with reference to FIG. 9 toFIG. 13.

Meanwhile, when the terminal transmits the uplink user plane data onlythrough the WLAN carrier, information for identifying the radio bearerin the aggregation entity may be added to the uplink user plane data,and the same may be received.

Furthermore, the base station may transmit and receive the downlink userplane data and the uplink user plane data by combination of the downlinkstructure and the uplink structure described above.

Meanwhile, a terminal and a base station may perform the aboveoperations according to at least one embodiment of the presentdisclosure.

According to an embodiment, the terminal may include: a receiving unitthat receives additional configuration information to further configurea WLAN carrier that uses an unlicensed frequency band and receives thedownlink user plane data through a WLAN carrier or a base stationcarrier that uses a licensed frequency band according to the additionalconfiguration information; and a transmitting unit that transmits uplinkuser plane data through the WLAN carrier or the base station carrieraccording to the additional configuration information.

For example, the receiving unit may receive the downlink user plane datathrough the WLAN carrier by an interworking function in the PDCP (PacketData Convergence Protocol) entity of the base station, and thetransmitting unit may transmit the uplink user plane data only throughthe base station carrier. Alternatively, the receiving unit may receivethe downlink user plane data through the WLAN carrier by an interworkingfunction in the PDCP (Packet Data Convergence Protocol) entity of thebase station, and the transmitting unit may transmit the uplink userplane data only through the WLAN carrier. Alternatively, the receivingunit may receive the downlink user plane data through the WLAN carrierand the base station carrier by a split function in the PDCP (PacketData Convergence Protocol) entity of the base station, and thetransmitting unit may transmit the uplink user plane data only throughthe base station carrier. Alternatively, the receiving unit may receivethe downlink user plane data through the structure of each embodimentdescribed with reference to FIG. 1 to FIG. 8. In addition, thetransmitting unit may transmit the uplink user plane data through thestructure of each embodiment described with reference to FIG. 9 to FIG.13.

Meanwhile, when the transmitting unit transmits the uplink user planedata only through the WLAN carrier, the transmitting unit may addinformation for identifying the radio bearer in the aggregation entityto the uplink user plane data, and the transmitting unit may transmitthe same.

Furthermore, the receiving unit may receive downlink controlinformation, data, or messages from the base station through acorresponding channel. In addition, the transmitting unit may transmituplink control information, data, or messages to the base stationthrough a corresponding channel.

A controller may control the overall operations of the terminal toperform the present disclosure in which: the E-UTRAN adds a WLAN as acarrier of the E-UTRAN to the terminal in the RAN level when theterminal transmits specific user plane data; the terminal effectivelyselects one of an E-UTRAN carrier and a WLAN carrier with respect to thedownlink and uplink in consideration of the wireless state, mobility, orpower consumption thereof; and the terminal transmits the user planedata.

The base station, according to an embodiment of the present disclosure,may include: a transmitting unit that creates and transmits additionalconfiguration information to further configure a WLAN carrier that usesan unlicensed frequency band and that transmits the downlink user planedata through a WLAN carrier or a base station carrier that uses alicensed frequency band according to the additional configurationinformation; and a receiving unit that receives the uplink user planedata through the WLAN carrier or the base station carrier according tothe additional configuration information.

For example, the transmitting unit may transmit the downlink user planedata through the WLAN carrier by an interworking function in the PDCP(Packet Data Convergence Protocol) entity of the base station, and thereceiving unit may receive the uplink user plane data only through thebase station carrier. Alternatively, the transmitting unit may transmitthe downlink user plane data through the WLAN carrier by an interworkingfunction in the PDCP (Packet Data Convergence Protocol) entity of thebase station, and the receiving unit may receive the uplink user planedata only through the WLAN carrier. Alternatively, the transmitting unitmay transmit the downlink user plane data through the WLAN carrier andthe base station carrier by a split function in the PDCP (Packet DataConvergence Protocol) entity of the base station, and the receiving unitmay receive the uplink user plane data only through the base stationcarrier. Alternatively, the transmitting unit may transmit the downlinkuser plane data through the structure of each embodiment described withreference to FIG. 1 to FIG. 8. In addition, the receiving unit mayreceive the uplink user plane data through the structure of eachembodiment described with reference to FIG. 9 to FIG. 13.

Meanwhile, when the terminal transmits the uplink user plane data onlythrough the WLAN carrier, the receiving unit may add information foridentifying the radio bearer in the aggregation entity to the uplinkuser plane data to then be received.

Furthermore, the transmitting unit and receiving unit may be used totransmit or receive signals, messages, or data that are necessary forexecuting the present disclosure to or from the terminal.

A controller may control the overall operations of the base station toperform the present disclosure in which: the E-UTRAN adds a WLAN as acarrier of the E-UTRAN to the terminal in the RAN level when theterminal transmits specific user plane data; the terminal effectivelyselects an E-UTRAN carrier and a WLAN carrier with respect to thedownlink and uplink in consideration of the wireless state, mobility, orpower consumption thereof; and the terminal transmits the user planedata.

Meanwhile, the present disclosure includes a detailed embodiment forsplitting and interworking the data by using the WLAN carrier describedabove. Hereinafter, the detailed description will be made of a split orinterworking method that is necessary for splitting or interworking auser plane data unit in the PDCP layer and for transmitting the userplane data through an E-UTRAN carrier and/or a WLAN carrier.

In order for the E-UTRAN to add a WLAN carrier to the E-UTRAN as acarrier of the RAN level and to transmit the user plane data through theE-UTRAN carrier and the WLAN carrier, a method for splitting (orrouting) or interworking a user plane data unit in the E-UTRAN layer 2may be considered.

For example, the PDCP entity may split data into first data to betransmitted through the E-UTRAN carrier and/or second data to betransmitted through the WLAN carrier and may transmit at least one ofthe first and second data. Then, a peered PDCP entity may receive (oraggregately receive) the at least one of first and second data.Alternatively, the PDCP entity may interwork the data to be transmittedthrough a WLAN carrier and may transmit the same, and a peered PDCPentity may receive the same. As another example, the RLC entity maysplit data in to first data to be transmitted through an E-UTRAN carrierand/or second data to be transmitted through a WLAN carrier and maytransmit at least one of the first and second data. A peered RLC entitymay receive (or aggregately receive) the at least one of first andsecond data. Alternatively, the RLC entity may interwork the data to betransmitted through a WLAN carrier and may transmit the same, and apeered RLC entity may receive the same.

However, in the related art, the PDCP layer is standardized based on theinterface with the RLC layer, and the RLC layer is standardized based onthe interface with the MAC layer. Therefore, when the PDCP layer or theRLC layer splits or interworks first data to be transmitted through anE-UTRAN carrier and second data to be transmitted through a WLAN carrierand transmits the same through a WLAN carrier, the PDCP layer or the RLClayer may not execute a normal function that is required by a lowerlayer. Accordingly, the PCCP layer or the RLC layer may not workcorrectly when transmitting and receiving data through a WLAN carrier.

For example, the PDCP layer may provide PDCP layer functions through aninterface that is standardized with a lower layer including the RLClayer. For example, the PDCP layer is able to operate handover withoutan error only when a notification stating a successful data transfer isreceived from the RLC layer. However, since such a standardizedinterface is not determined when adding and using a WLAN carrier, theremay be an error in the operation of the PDCP layer. In the presentspecification, the PDCP layer and the RLC layer may be configured in theterminal or in the base station, and an entity that executes functionsin each layer will be expressed as a PDCP entity and an RLC entity.Accordingly, a PDCP layer and a PDCP entity may be interchangeably usedas necessary, and the PDCP layer and the PDCP entity may be used in thesame sense. Likewise, an RLC layer and an RLC entity may beinterchangeably used as necessary, and the RLC layer and the RLC entitymay be used in the same sense.

As described above, when transmitting specific user plane data, thetypical E-UTRAN cannot: add a WLAN carrier as a carrier to the E-UTRAN;and split or interwork the user plane data unit in the E-UTRAN layer 2to then transmit the user plane data through an E-UTRAN carrier and aWLAN carrier. Since the PDCP layer among sub-layers in the E-UTRAN layer2 can provide functions of the PDCP layer through a standardizedinterface with a lower layer including the RLC layer, existingoperations in the PDCP layer may not be performed correctly even if theuser plane data is transferred through the WLAN carrier.

The present disclosure has been made in order to solve the problemsabove, and has an objective of providing a split or interworking methodthat is necessary for: adding a WLAN carrier as a carrier to theE-UTRAN; splitting or interworking a user plane data unit in the PDCPlayer; and transmitting the user plane data through the E-UTRAN carrierand/or the WLAN carrier.

For the E-UTRAN to add a WLAN carrier as a carrier of the E-UTRAN to theterminal in the RAN level and to transmit or receive the user plane datathrough the E-UTRAN carrier and the WLAN carrier, a protocol structurefor the same and the operation of each layer should be provided.

The operation in which the E-UTRAN adds a WLAN carrier as a carrierconceptually refers to the operation in which the terminal and the basestation add an additional function for the WLAN carrier to the typicalE-UTRAN cell to then be configured.

To add a WLAN carrier as a carrier of the E-UTRAN to the terminal in theRAN level and to transmit the user plane data in a radio bearer unitthrough the E-UTRAN carrier and/or the WLAN carrier, the E-UTRAN maysplit (or route) or interwork a user plane data unit in the sub-layer ofthe E-UTRAN Layer 2, and may transmit the same.

For example, the PDCP entity (or RLC entity) may split the data to betransmitted through the E-UTRAN carrier and the data to be transmittedthrough the WLAN carrier and may transmit the same, and a peered PDCPentity (or RLC entity) may receive (or aggregately receive) the same.Alternatively, the PDCP entity (or RLC entity) may interwork the data tobe transmitted through a WLAN carrier and may transmit the same, and apeered PDCP entity (or RLC entity) may receive the same.

<Data Transfer Path>

Hereinafter, the description will be made of a scenario in which theE-UTRAN adds a WLAN carrier as a carrier of the E-UTRAN in the RAN leveland transmits the user plan data to or receives the user plane data fromthe terminal in a radio bearer unit through an E-UTRAN carrier and/or aWLAN carrier with reference to the drawings. That is, the uplink anddownlink data transmission path scenario will be described when the PDCPlayer transmits user data by splitting the user data into first data tobe transmitted through an E-UTRAN carrier and/or second data to betransmitted through a WLAN carrier or by interworking the first data andthe second data.

FIG. 16 is a view exemplary illustrating a data transmission path byusing an E-UTRAN carrier and a WLAN carrier in accordance with at leastone embodiment.

Referring to FIG. 16, a base station 1600 may transmit or receive uplinkor downlink data to or from a terminal 1620 through an eNB carrier. Inaddition, a WLAN termination 1610 may also transmit or receive uplink ordownlink data to or from the terminal 1620 by using a WLAN carrier. Thatis, both the eNB carrier and the WLAN carrier may process the uplink anddownlink data.

FIG. 17 is a view exemplary illustrating a data transmission path byusing an E-UTRAN carrier and a WLAN carrier in accordance with anotherembodiment.

Referring to FIG. 17, the base station 1600 may transmit or receiveuplink or downlink data to or from a terminal 1620 through an eNBcarrier. On the contrary, the WLAN termination 1610 may transmit onlythe downlink data to the terminal 1620 by using a WLAN carrier. That is,the downlink data may be transmitted by using both the eNB carrier andthe WLAN carrier, but the uplink data may be transmitted by using onlythe eNB carrier.

FIG. 18 is a view exemplary illustrating a data transmission path byusing an E-UTRAN carrier and a WLAN carrier in accordance with stillanother embodiment.

Referring to FIG. 18, both the uplink and downlink data may be processedby using a WLAN carrier. That is, the base station 1600 and the WLANtermination 1610 may transmit or receive the downlink and uplink data toor from the terminal 1620 by using the WLAN carrier.

FIG. 19 is a view exemplary illustrating a data transmission path byusing an E-UTRAN carrier and a WLAN carrier in accordance with yetanother embodiment.

Referring to FIG. 19, the base station 1600 may receive the uplink datafrom the terminal 1620 by using an eNB carrier. In addition, thedownlink data may be transmitted through the WLAN termination 1610 byusing a WLAN carrier. That is, the eNB carrier may process the uplinktransmission and the WLAN carrier may process the downlink transmission,respectively.

In the case of FIG. 16 or FIG. 18, a method is required for enabling thebase station 1600 to transmit the downlink user data to the terminal1620 through the WLAN termination 1610, and for enabling the terminal1620 to transmit the uplink user data to the base station 1600 throughthe WLAN termination 1610.

Meanwhile, in the case of FIG. 17 or FIG. 19, a method is required forenabling the base station 1600 to transmit downlink user data to theterminal 1620 through the WLAN termination 1610.

The eNB carrier means an E-UTRAN carrier and a carrier that is formedthrough E-UTRAN wireless resources.

<PDCP Interface Layer>

The PDCP layer provides the user plane data transmission, the headercompression, a ciphering service, or the like. In addition, the PDCPlayer expects lower layers to perform the services, such as:

-   -   an acknowledged data transfer service including the indication        of a successful delivery of the PDCP PDUs,    -   an unacknowledged data transfer service,    -   an in-sequence delivery, except for re-establishment of lower        layers, or    -   duplicate discarding, except for re-establishment of lower        layers.

Meanwhile, competition-based multiple access occurs in the WLAN, incomparison to the E-UTRAN provided with the wireless resource managementby the base station scheduling. Therefore, a radio bearer for theunidentified data transfer service that is suitable for delay-sensitiveservices may not be appropriate to be transmitted through a WLANcarrier. Therefore, the following description will be made in detail ofthe acknowledged data transmission including an indication of asuccessful delivery of the PDCP data (for example, PDCP PDUs or PDCPSDUs) among the services described above. Hereinafter, the operation ofthe terminal for receiving data through a WLAN wireless link will bedescribed by exemplifying the PDCP PDUs. However, the PDCP PDUs are onlyan example, and it may be applied to user plane data, data, PDCP SDUs,or PDCP SDUs that are associated with a sequence number in the samemanner. That is, the embodiment of the present disclosure encompassesthe case in which user plane data, data, PDCP SDUs, or PDCP SDUs thatare associated with a sequence number are used instead of the PDCP PDUs,which will be described below.

Most of the user plane data that requires lossless transmission may usean acknowledged mode (AM) RLC. The AM RLC ensures lossless datatransmission through the retransmission. A receiving end of the AM RLCentity sends an RLC status report to provide a negative acknowledgementfor RLC PDUs that have not been received correctly. When the RLC statusreport is received, a transmitting end of the AM RLC entity retransmitsthe same. The retransmission is repeatedly performed until all the RLCPDUs are correctly received by the receiving end of the AM RLC entity oruntil the number of retransmissions reaches the maximum.

Meanwhile, when the upper layer requests the PDCP re-establishment, theterminal may:

-   -   reset a header compression protocol for the uplink and start        with an IR state in the U-mode (if configured);    -   apply a ciphering algorithm and key provided by upper layers        during the re-establishment procedure;    -   from the first PDCP SDU for which a successful delivery of the        corresponding PDCP PDU has not been acknowledged by lower        layers, perform the retransmission or transmission of all the        PDCP SDUs that have already been associated with PDCP SNs in        ascending order of the COUNT values associated to the PDCP SDU        prior to the PDCP re-establishment as described below;    -   perform the header compression of the PDCP SDU (if configured);    -   perform the ciphering of the PDCP SDU by using the COUNT value        associated with the PDCP SDU; and    -   submit the resulting PDCP Data PDU to a lower layer.

With regard to the user plane radio bearer for the lossless transmissionas described above, the PDCP entity may receive anindication/acknowledgment for a successful delivery of the PDCP PDUsfrom the RLC entity, and may retransmit the PDCP SDUs when performingthe PDCP re-establishment.

Meanwhile, to control the PDCP sequence numbers to not be duplicated,the PDCP entity requires an indication/acknowledgment for a successfuldelivery of the PDCP PDUs. If the indication/acknowledgment for asuccessful delivery of the PDCP PDUs that are transmitted through a WLANcarrier is not provided, the PDCP entity may create PDCP data thatexceeds a limited PDCP sequence number, and in this case, it isdifficult for the PDCP entity to process the data in sequence.

When transmitting user plane data for a specific radio bearer by addinga WLAN carrier as a carrier, the E-UTRAN may split or interwork the userplane data in the PDCP layer, and may transmit the user plane datathrough a WLAN carrier (or an E-UTRAN carrier and WLAN carrier). In thiscase, the PDCP entity can retransmit the PDCP SDUs when performing thePDCP re-establishment only when the PDCP entity receives anindication/acknowledgment for a successful delivery of the PDCP PDUsfrom an entity that transmits or receives the PDCP PDUs through a WLANcarrier. Furthermore, the PDCP entity is able to make a control tocreate the PDCP data within limited PDCP sequence numbers only when thePDCP entity receives an indication/acknowledgment for a successfuldelivery of the PDCP PDUs from an entity that transmits or receives thePDCP PDUs through a WLAN carrier.

Accordingly, the entity that interfaces with the PDCP entity in the basestation and/or the terminal and transmits or receives the PDCP PDUsthrough a WLAN carrier should provide an interfaced PDCP entity with anindication/acknowledgment for a successful delivery of the PDCP PDUs.

As described above, the present disclosure provides a method forperforming a typical PDCP transmission function when the base stationprocesses data by adding a WLAN carrier as a carrier.

FIG. 20 is a flowchart for explaining operation of a terminal, accordingto an embodiment of the present disclosure.

The terminal, according to an embodiment of the present disclosure,provides a method that includes: configuring an interface and a userplane entity for transmitting data to or receiving data from the basestation through a WLAN carrier; receiving user plane data from the basestation through the interface; and transmitting, to the base station,control information indicating the successful or unsuccessful receptionof the user plane data through the interface or the interface betweenthe terminal and the base station.

Referring to FIG. 20, the terminal may execute configuring an interfaceand a user plane entity for transmitting data to or receiving data fromthe base station through a WLAN carrier (S2010). For example, theterminal may configure a data transmission/reception interface with thebase station by using a WLAN carrier. As shown in the scenario describedwith reference to FIG. 16 to FIG. 19, the terminal of the presentdisclosure may configure a data transmission/reception interface througha WLAN carrier for each of a variety of scenarios. For example, theterminal may configure an interface for receiving the downlink data thatis transmitted by the base station through a WLAN termination.Alternatively, the terminal may also configure an interface fortransmitting the uplink data through a WLAN carrier. Alternatively, theterminal may configure an interface for transmitting data to orreceiving data from the base station by using both the E-UTRAN carrierand the WLAN carrier.

Meanwhile, the terminal may configure a user plane entity to transmitdata or receive data through a WLAN carrier. The user plane entityrefers to a functional entity for transmitting or receiving data byusing a WLAN carrier. The user plane entity may be configured with anentity that is peered with the base station or may be configured with anentity that is peered with the WLAN termination.

In addition, the user plane entity may be configured to be associatedwith each data radio bearer. That is, it may be determined whether theuser plane entity is configured for each data radio bearer. For example,the user plane entity may not be configured for a data radio bearer thatdoes not use a WLAN carrier, and the user plane entity may be configuredonly for a data radio bearer that uses a WLAN carrier.

The terminal may receive configuration information for configuring theuser plane entity from the base station. The configuration informationfor configuring the user plane entity may be included in the radiobearer configuration information and received with the radio bearerconfiguration information. That is, each piece of the radio bearerconfiguration information may include the configuration information forthe user plane entity that is configured for each radio bearer. Forexample, in the case of a radio bearer that transmits or receives dataonly by using an E-UTRAN carrier, the radio bearer configurationinformation may not include the configuration information forconfiguring the user plane entity. On the contrary, in the case of adata radio bearer that uses a WLAN carrier, the radio bearerconfiguration information may include the configuration information forconfiguring the user plane entity. The radio bearer configurationinformation may be received through an upper layer signaling. Forexample, the radio bearer configuration information may be included inan RRC message, such as an RRC connection reconfiguration message andreceived with the RRC message.

The terminal may execute receiving the user plane data from the basestation through the configured interface (S2020). For example, asdescribed with reference to FIG. 16 to FIG. 19, the terminal may receivethe user plane data through a WLAN carrier according to each scenario.In this case, the data may be received through the interface that isconfigured in the step S2010 and uses a WLAN carrier. That is, theterminal may process the data received through the WLAN carrier by theuser plane entity.

The terminal may execute transmitting, to the base station, controlinformation that indicates the successful or unsuccessful reception ofthe user plane data through the interface between the terminal and thebase station (S2030). For example, the control information is intendedto acknowledge or indicate the successful reception of the datatransmitted by the PDCP entity described above, and the controlinformation may include at least one of: i) the highest PDCP SDU/PDUsequence number that is successfully received/delivered in sequence bythe terminal among the PDCP SUDs/PDUs that are received from theeNB/WLAN termination; ii) a PDCP sequence number that is regarded to belost; transmission packet information that contains PDCP data of thehighest PDCP sequence number that is successfully received by theterminal through the WLAN carrier; iii) information (for example, asequence number) on the user plane data that is successfully received bythe terminal through the WLAN carrier; or iv) information on the userplane data that is regarded to be lost. That is, the terminal maytransmit, to the base station, the control information that includes theinformation indicating whether or not the data is successfully receivedthrough the WLAN carrier.

In this case, the control information may be provided from the userplane entity or the PDCP entity. For example, the user plane entity maycheck whether the PDCP PDU has been successfully received. If the PDCPPDU is missing or is received out of sequence, the user plane entity mayinclude information on the same in the control information and transmitthe control information to the base station. Alternatively, the PDCPentity may check whether the PDCP PDU has been successfully received. Ifthe PDCP PDU is missing or is received out of sequence, the PDCP entitymay include information on the same in the control information andtransmit the control information to the base station. Alternatively, thetransmission of the control information may be triggered based on thepolling of the base station, or based on a period or timer that is setby the base station. In this case, the terminal may receive the periodor timer for transmitting the control information in advance.

Meanwhile, the control information may be transmitted to the basestation through an interface that is configured to process the data byusing a WLAN carrier. Alternatively, the control information may betransmitted to the base station through an interface between theterminal and the base station by using an E-UTRAN carrier. That is, thecontrol information may be transmitted through an interface using theWLAN carrier, or the control information may be transmitted through aninterface using only the E-UTRAN carrier.

As described above, when the user plane entity or the PDCP entityconfigured in the terminal processes the data by using the WLAN carrier,a PDCP transmission function within a limited PDCP sequence number or aPDCP PDU retransmission function according to the PDCP re-establishmentmay be provided by providing the base station with the controlinformation indicating the successful or unsuccessful reception. Inaddition, the typical functions provided by the PDCP entity may also beprovided in the case of the data transmission and reception by using theWLAN carrier.

Hereinafter, interface configuration and control informationtransmission according to at least one embodiment will be described withreference to the drawings.

Method for Using Tunnel-Based User Plane Protocol

FIG. 21 is a view exemplary illustrating a user plane protocol structurefor transmitting user plane data according to at least one embodiment ofthe present disclosure.

Hereinafter, for convenience and ease of understanding, in order toseparate an interface configured by using the WLAN carrier from anotherinterface configured by using the typical E-UTRAN carrier, the interfaceconnected between the base station and the terminal through the WLANcarrier is denoted as an Ux interface. For example, the Ux interface mayrepresent an interface between a WLAN termination and a terminal. Asanother example, the Ux interface may refer to an interface between abase station, a WLAN termination, and a terminal.

In accordance with at least one embodiment, the terminal and the basestation, or the terminal and the WLAN termination may be provided withan Ux user plane protocol to deliver the control information forproviding an indication or acknowledgment for a successful delivery ofthe PDCP PDUs through the Ux interface. The Ux user plane protocol mayrefer to a protocol for controlling the E-UTRAN wireless network userplane data transmission through the Ux interface, and the Ux user planeprotocol may refer to as an Ux UP or an Ux UP protocol for convenience,hereinafter.

Referring to FIG. 21, the Ux UP protocol may be positioned in the userplane of a radio network layer on the interface that is connectedbetween the base station 1600 and the terminal 1620 through a WLAN.Alternatively, the Ux UP protocol may be positioned in the Layer 2 userplane on the interface (Ux interface) that is connected between the basestation 1600 and the terminal 1620 through a WLAN. Alternatively, the UxUP protocol may be positioned in the PDCP layer user plane on theinterface (Ux interface) that is connected between the base station 1600and the terminal 1620 through a WLAN. Alternatively, the Ux UP protocolmay be positioned in the RLC layer user plane on the interface (Uxinterface) that is connected between the base station 1600 and theterminal 1620 through a WLAN. Alternatively, the Ux UP protocol may bepositioned in the lower layer user plane of the PDCP on the interface(Ux interface) that is connected between the base station 1600 and theterminal 1620 through a WLAN. Alternatively, the Ux UP protocol may bepositioned in the user plane between the PDCP and the RLC layer on theinterface (Ux interface) that is connected between the base station 1600and the terminal 1620 through a WLAN.

The entity in the terminal or the base station for processing the Ux UPprotocol may be variously referred to as a user plane entity, a Ux UPprotocol entity, a Ux protocol instance or Ux interlocking entity, a Uxinterlocking instance or interlocking entity, an interlocking protocolentity, an interlocking entity, an aggregation entity, a transmissionprotocol entity, or the like. However, in the following description, forconvenience and ease of understanding, a user plane entity or an Ux UPprotocol entity will be used.

The user plane entity may be associated with a single radio bearer (forexample, data radio bearer). Alternatively, each user plane entity maybe associated with a single E-RAB.

If configured, the user plane entity may be configured in the basestation and terminal in which the radio bearer is setup/added/configured on the Ux interface. For example, the base stationmay include user plane entity configuration information for configuringthe user plane entity in the radio bearer configuration information(DRB-ToAddMod) that is configured to be radio bearer-specific (or foreach radio bearer), and the base station may transfer the same to theterminal through an RRC reconfiguration message.

As shown in FIG. 21, the Ux UP protocol data or the Ux UP PDU(s) may beincluded in a GTP-U protocol. Alternatively, as shown in FIG. 21, the UxUP protocol data, the Ux UP SDU(s), the PDCP SDU, or the PDCP PDU(s) maybe included in a GTP-U protocol header. Alternatively, as shown in FIG.21, the Ux UP protocol data, the Ux UP SDU(s), the PDCP SDU, or the PDCPPDU(s) may be included in a GTP-U extension header. Alternatively, asshown in FIG. 21, the Ux UP protocol data, the Ux UP SDU(s), the PDCPSDU(s), or the PDCP PDU(s) may be included in a GTP-U extension headerby defining a field (or container) for the Ux UP protocol.

Meanwhile, the Ux UP protocol may provide a sequence number for the userdata (or PDCP SDUs/PDUs) that is transmitted from the base station tothe terminal through a WLAN carrier. Alternatively, the Ux UP protocolmay provide a sequence number for the user data (or PDCP SDUs/PDUs) thatis transmitted from the terminal to the base station through a WLANcarrier.

The Ux UP protocol may also provide the control information toacknowledge/indicate a successful delivery of the PDCP SDUs/PDUs thatare transmitted from the base station to the terminal through a WLANcarrier. Alternatively, the Ux UP protocol may provide the controlinformation to acknowledge/indicate a successful delivery of the PDCPSDUs/PDUs that are transmitted from the terminal to the base stationthrough a WLAN carrier.

When the user plane data for a specific radio bearer (or E-RAB) istransmitted through an Ux interface, the user plane entity may operatethe procedure to provide the control information to acknowledge/indicatea successful delivery of the PDCP SDUs/PDUs.

For example, in the case of the downlink data transmission, the basestation may allocate consecutive Ux-UP sequence numbers to therespective Ux-UP packets to be transmitted. The terminal may detectwhether the Ux-UP packet has been lost in a regular interval that is setby the base station or when a request is received from the base station.Alternatively, the terminal may detect whether the Ux-UP packet has beenlost constantly or according to a polling field setting included in theUx-UP packet header by the base station. Alternatively, in the case ofreceiving the downlink data by using both the E-UTRAN carrier and theWLAN carrier, the terminal may detect whether the packet has been lostby means of the reordering function of the PDCP entity, and may transferthe same to the user plane entity.

If a Ux-UP packet is detected to be out of sequence or to have beenlost, the terminal may transmit, to the base station, at least one pieceof information of: the highest Ux-UP sequence number that issuccessfully received; the highest PDCP sequence number that issuccessfully received; or a PDCP sequence number that is regarded tohave been lost. Alternatively, the terminal may transmit, to the basestation, at least one piece of information of: the highest Ux-UPsequence number that is successfully received; the highest PDCP sequencenumber that is successfully received; or a PDCP sequence number that isregarded to have been lost constantly or according to a constant period,a request received from the base station, or a polling field setting.

Alternatively, the terminal may detect whether the Ux-UP packet has beenlost in a constant period set by the base station, by a request of thebase station, by way of a polling field setting that is included in theUx-UP packet header by the base station, or constantly. If a Ux-UPpacket is detected to be out of sequence or to have been lost, theterminal may transmit, to the base station, at least one piece ofinformation of: the highest PDCP sequence number that is successfullyreceived; the sequence number of the Ux-UP packet that is declared tohave been lost by the terminal; or the sequence numbers of the PDCP PDUsthat are declared to have been lost by the terminal. At least one pieceof information of: the highest PDCP sequence number that is successfullyreceived by the terminal; the sequence number of the Ux-UP packet thatis declared to have been lost by the terminal; or the sequence numbersof the PDCP PDUs that are declared to have been lost by the terminal maybe transmitted by means of the configuration information describedabove.

For example, the control information may be transmitted through anuplink Ux interface. As another example, the control information may betransmitted through an uplink Uu interface between the base station andthe terminal. The Uu interface refers to the typical interface betweenthe base station and the terminal through an E-UTRAN carrier. Thecontrol information may be provided by the PDCP control PDU when it istransmitted through the Uu interface. For example, a PDCP status reportmay be used. Alternatively, it may be provided through a new format ofPDCP control PDU for the control information transmission.

Meanwhile, the terminal may declare, as being lost, the Ux-UP packet,which has not been received according to a constant period set by thebase station or according to a request of the base station.Alternatively, the terminal may declare, as being lost, the Ux-UPpacket, which has not been received or according to a polling fieldsetting included in the Ux-UP packet header from the base station.Alternatively, the terminal may declare, as being lost, the Ux-UPpacket, which has not been received after receiving the Ux-UP packetthat is out of sequence. Alternatively, the terminal may declare, asbeing lost, the Ux-UP packet, which has not been received afterreceiving the Ux-UP packet that is out of sequence and after the lapseof the expiration time by the base station.

Until now, the case has been described in which the user plane entitychecks the successful or unsuccessful reception of the user plane datathat is received by using a WLAN carrier and transmits the controlinformation. However, a method has been described in which the userplane entity identifies the data that is out of sequence or is lost byusing a separate sequence number for the data received through a WLANcarrier.

Meanwhile, as another method, the Ux UP protocol may not provide asequence number for the user data (or PDCP SDUs/PDUs) that istransmitted through a WLAN carrier, and the Ux UP protocol may providethe terminal with the control information to acknowledge/indicate asuccessful delivery of the PDCP SDUs/PDUs through a WLAN carrier byusing sequence numbers of the SDUs/PDCP PDUs.

For example, in the case of the downlink data transmission, the terminalmay detect whether the Ux-UP packet has been lost constantly, accordingto a constant period set by the base station, by a request of the basestation, or according to a polling field setting by the base station.

If an Ux-UP packet is detected to be out of sequence or to have beenlost, the terminal may transmit, to the base station, the highest PDCPsequence number that is successfully received. Alternatively, theterminal may transmit, to the base station, the highest PDCP sequencenumber that is successfully received constantly or according to aconstant period, in response to a request of the base station, oraccording to a polling field setting included in the Ux-UP packet headerfrom the base station.

Alternatively, the terminal may detect whether the Ux-UP packet has beenlost constantly, according to a constant period set by the base station,in response to a request of the base station, or according to a pollingfield setting. If an Ux-UP packet is detected to be out of sequence orto have been lost, the terminal may transmit, to the base station, atleast one piece of information of: the highest PDCP sequence number thatis successfully received; or the sequence numbers of the PDCP PDUs thatare declared as being lost by the terminal. Alternatively, the terminalmay transmit, to the base station, at least one piece of information of:the highest PDCP sequence number that is successfully received; or thesequence numbers of the PDCP PDUs that are declared as being lost by theterminal constantly, according to a constant period, in response to arequest of the base station, or according to a polling field setting. Inthis case, information on the highest PDCP sequence number that issuccessfully received and information on the sequence numbers of thePDCP PDUs that are declared as being lost by the terminal may beincluded in the control information.

For example, the control information may be transmitted through anuplink Ux interface. As another example, the control information may betransmitted through an uplink Uu interface between the base station andthe terminal. The control information may be provided through the PDCPcontrol PDU when it is transmitted through the Uu interface. Forexample, the control information may be transmitted through a PDCPstatus report. Alternatively, the configuration information may betransmitted through a new format of PDCP control PDU.

Meanwhile, the terminal may declare, as being lost, the Ux-UP packet,which has not been received: in a constant period set by the basestation; by a request of the base station; by a polling field settingthat is included in the Ux-UP packet header from the base station;constantly; after the terminal receives the Ux-UP packet that is out ofsequence; or after the lapse of expiration time by the base stationsince the terminal receives the Ux-UP packet that is out of sequence.

Until now, although the description has been made of the transmission ofthe configuration information that indicates a successful data deliverywhen the terminal receives the downlink data, the same operation may beapplied to the case where the base station receives the uplink data withthe replacement of the entity by the base station.

Meanwhile, in the case of the downlink transmission, the base stationmay remove buffered PDCP SDUs/PDUs according to the feedback of the PDCPSDUs/PDUs that are successfully delivered. Likewise, in the case of theuplink transmission, the terminal may remove buffered PDCP SDUs/PDUsaccording to the feedback of the PDCP SDUs/PDUs that are successfullydelivered.

FIG. 22 is a view exemplary illustrating a user plane protocol structurefor the transmission of the user plane data, according to anotherembodiment of the present disclosure.

Although the WLAN termination 1610 performs the routing in the IP layer,the present disclosure may encompass the case where the WLAN termination1610 performs the routing/switching or MAC switching in the data linklayer.

As shown in FIG. 22, a GTP tunnel may be set up in a base station 1600and a terminal 1620. For example, in the case of performing the downlinktransmission through a WLAN carrier as shown in the scenarios of FIG. 16to FIG. 19, the base station 1600 may deliver, through a GTP protocol(or a GTP-U protocol, a WLAN interworking tunnel protocol, or a certaintunnel protocol), the user data to be transmitted by a split orinterworking function through a WLAN carrier by using the downlinktunnel. As another example, in the case of performing the uplinktransmission through a WLAN carrier as shown in the scenarios of FIG. 16to FIG. 18, the terminal 1620 may deliver, through a GTP protocol (or aGTP-U protocol, a WLAN interworking tunnel protocol, or a certain tunnelprotocol), the user data to be transmitted by a split or interworkingfunction through a WLAN carrier by using the uplink tunnel.

The above-described tunnel (for example, a GTP tunnel or a certainheader encapsulation-based tunnel) between the base station 1600 and theterminal 1620 may be used to deliver an encapsulated user data packet(or E-UTRAN Layer 2 SDU/PDU or E-UTRAN Layer 2 user data) between a pairof given tunnel endpoints.

For example, when the PDCP layer or PDCP entity splits data into orinterworks first data to be transmitted through an E-UTRAN carrierand/or second data to be transmitted through a WLAN carrier, the tunnelbetween the base station 1600 and the terminal 1620 may be used todeliver PDCP SDUs or PDCP PDUs between a pair of given tunnel endpoints.

As another example, when the RLC layer or RLC entity splits data into orinterworks the data to be transmitted through an E-UTRAN carrier and/orthe data to be transmitted through a WLAN carrier, the tunnel betweenthe base station 1600 and the terminal 1620 may be used to deliver RLCPDUs between a pair of given tunnel endpoints.

A tunnel protocol header (for example, a GTP header or a header on acertain header encapsulation-based tunnel) of the tunnel between thebase station 1600 and terminal 1620 includes a tunnel endpointidentification information (for example, TEID) field. This fieldunambiguously identifies the tunnel endpoints in the receiving tunnelprotocol entity (a GTP-U protocol entity, a GTP protocol entity, aninterworking entity, an interworking protocol entity, a GTP tunnelentity, a GTP-U tunnel entity, a GTP entity, a GTP-U entity, anaggregation entity, an aggregation protocol entity, or a transmissionprotocol entity; hereinafter, referred to as a tunnel protocol entity).

The tunnel endpoint included in the tunnel protocol header may indicatea tunnel to which a specific user data packet belongs.

Alternatively, the tunnel endpoint included in the tunnel protocolheader may indicate a radio bearer or radio bearer entity to which aspecific user data packet belongs. Alternatively, the tunnel endpointincluded in the tunnel protocol header may map a specific user datapacket with a corresponding radio bearer or radio bearer entity.

The tunnel endpoint identification information (for example, TEID)included in the tunnel protocol header may demultiplex the incomingtraffic and transfer the same to the corresponding user plane radiobearer entity.

For example, when the base station PDCP entity splits data into orinterworks the data to be transmitted through an E-UTRAN carrier and/orthe data to be transmitted through a WLAN carrier, the terminal thatreceives the data through the downlink tunnel may transfer the receiveddata/PDCP SDUs/PDUs to the peered or corresponding PDCP entity in theterminal through the tunnel endpoint identification information.

Entity Usage for Aggregation/Interworking Between Base Station and WLANTermination

For enabling the E-UTRAN to add a WLAN carrier as a carrier in the PDCPlayer and to transmit the downlink user plane data traffic bysimultaneously using a carrier and the WLAN carrier, an aggregationentity for the aggregation/interworking between the base station and theWLAN termination may be required. The aggregation entity may be used toencompass an interworking entity, an LTE-WLAN adaptation entity, aninterworking function, a logical entity for the LTE-WLAN aggregation,and an LTE-WLAN aggregation entity. In addition, in some cases, theaggregation entity may refer to the above-described user plane entity.

The aggregation entity may be a standalone entity, or the aggregationentity may be a functional entity of another network. For example, whenthe base station and the WLAN termination are co-located as anintegrated device, the aggregation entity may be a functional entityincluded in the integrated device. As another example, the aggregationentity may be a functional entity included in the WLAN termination inthe scenario in which the base station and the WLAN termination are notco-located. As another example, the aggregation entity may be afunctional entity included in the base station in the scenario in whichthe base station and the WLAN termination are not co-located.

The aggregation entity may be implemented to be an upper layer entitythan L1/L2. For example, when the aggregation entity is configured as afunctional entity included in the WLAN termination, it may operate asbeing an upper layer entity than WLAN L1/L2 to transmit user plane datato the terminal through the WLAN L1/L2. As another example, when theaggregation entity is configured as a functional entity included in thebase station, it may operate as being an upper layer entity (forexample, an IP layer, a session layer, or an application layer) totransmit user plane data to the terminal through the WLAN termination.As another example, when the aggregation entity is configured as afunctional entity included in the base station, it may operate as beingan entity that executes a function of transmitting the PDCP PDUs throughthe WLAN termination to transmit user plane data to the terminal throughthe WLAN termination. As another method, the aggregation entity may beconfigured as a function in the WLAN L2 so that the WLAN L2 entity mayimplement the operation for the same.

The aggregation entity may receive the PDCP PDUs from the PDCP entity ofthe base station. Alternatively, the aggregation entity may receive thePDCP PDUs by making a request for the same to the PDCP entity of thebase station.

The aggregation entity may transmit the received PDCP PDUs to theterminal through a WLAN carrier. Alternatively, the aggregation entitymay transmit the received PDCP PDUs to the terminal by using a WLANL1/L2 protocol. Alternatively, the aggregation entity may transmit thereceived PDCP PDUs to the terminal through the WLAN termination (or WLANcarrier) by using IP communication.

The terminal may transfer the PDCP PDUs that are received through theWLAN carrier to the corresponding PDCP entity in the terminal.Alternatively, the terminal may transfer the PDCP PDUs that are receivedby using the WLAN L1/L2 protocol in the terminal to the correspondingPDCP entity in the terminal.

The base station may split and transmit the data traffic that belongs toa specific bearer in the PDCP layer through the base station and theWLAN termination. That is, to transmit the user plane data in a radiobearer unit through an E-UTRAN carrier and a WLAN carrier, the PDCPentity may split the PDCP PDUs into an associated RLC entity and/or anassociated aggregation entity to then be submitted. For the PDCP entityto transmit the user plane data in a radio bearer unit through anE-UTRAN carrier and a WLAN carrier, the base station may be configuredto enable the terminal to transfer the PDCP PDUs that are receivedthrough a WLAN carrier (or through a WLAN L1/L2 protocol or through aWLAN wireless receiving function) with respect to a specific bearer tothe corresponding PDCP entity of the specific bearer in the terminal.Alternatively, for the PDCP entity to transmit the user plane data in aradio bearer unit through an E-UTRAN carrier and a WLAN carrier, thebase station may include and send information by which the terminal maytransfer the PDCP PDUs that are received through a WLAN carrier (orthrough a WLAN L1/L2 protocol or through a WLAN wireless receivingfunction) with respect to a specific bearer to the corresponding PDCPentity of the specific bearer in the terminal.

FIG. 23 is a view exemplary illustrating a user plane protocol structurefor the transmission of user plane data, according to still anotherembodiment of the present disclosure.

When the base station 1600 and the WLAN termination 1610 are notco-located, the user plane data (PDCP PDUs) may be delivered through aGTP-U protocol in the interface between the base station 1600 and theWLAN termination 1610. When the base station 1600 and the WLANtermination 1610 are not co-located, and if the interface between thebase station 1600 and the WLAN termination 1610 is associated with anE-RAB for a bearer that is provided through the base station 1600 andWLAN termination 1610, the GTP-U may deliver the PDCP PDUs.

When the E-UTRAN adds a WLAN carrier as a carrier, and when the LTE-WLANaggregation is configured to transmit the downlink user data traffic byusing both the E-UTRAN carrier and the WLAN carrier, a user data beareris set up in the interface between the base station 1600 and the WLANtermination 1610, and a user plane protocol instance (UP protocolentity) is established in the base station 1600 and the WLAN termination1610, respectively, as shown in FIG. 23.

Each user plane protocol instance or UP protocol entity in the interfacebetween the base station 1600 and the WLAN termination 1610 isassociated with a single E-RAB. Therefore, each E-RAB may identify auser plane data bearer in the interface between the base station 1600and the WLAN termination 1610, an endpoint of the user plane data bearerof the base station 1600 that is associated with the correspondingbearer, or an endpoint of the WLAN termination 1610 that is associatedwith the corresponding bearer, respectively, by using a GTP tunnelendpoint IE (Information element).

The aggregation entity included in the WLAN termination 1610 may includethe user plane instance/entity in the WLAN termination 1610 describedabove. Alternatively, the aggregation entity may operate in associationwith the user plane instance/entity in the WLAN termination 1610described above. Alternatively, the aggregation entity may operate asthe user plane instance/entity in the WLAN termination 1610 describedabove.

As another method, when the base station 1600 and the WLAN termination1610 are not co-located, the user plane data (PDCP PDUs) may be includedin the payload of the IP protocol to be transmitted in the interfacebetween the base station 1600 and the WLAN termination 1610. The basestation 1600 may include the PDCP PDUs (user plane data) to betransmitted to the terminal 1620 through the WLAN termination 1610 inthe data field of the IP packet, and the base station 1600 may send thesame to the destination of the IP address of the terminal 1620 throughthe WLAN termination 1610.

As another method, when the base station 1600 and the WLAN termination1610 are not co-located, the user plane data (PDCP PDUs) may be includedin the payload of the WLAN L2 (or WLAN MAC) protocol to be transmittedin the interface between the base station 1600 and the WLAN termination1610. The base station 1600 may include the PDCP PDUs (user plane data)to be transmitted to the terminal 1620 through the WLAN termination 1610in the data field of the WLAN L2 (or WLAN MAC) frame, and the basestation 1600 may send the same to the destination of the WLAN MACaddress of the terminal 1620 through the WLAN termination 1610.

When it is determined to trigger the feedback on the downlink datatransfer, the user plane protocol instance (UP protocol entity) includedin the WLAN termination 1610 may transfer, to the base station 1600, theinformation, such as the highest PDCP PDU sequence number that issuccessfully transmitted to the terminal 1620 among the PDCP PDUsreceived from the base station 1600, a buffer size for the correspondingE-RAB, a user plane protocol instant packet that is regarded to havebeen lost, or the like.

To this end, the base station 1600 may receive the information on thesuccessful reception of the PDCP PDUs from the terminal 1620 in thefollowing manners. The function for receiving the configurationinformation on the successful reception of the PDCP PDUs from theterminal 1620 may be included in the aggregation entity function. Asdescribed below, when the terminal 1620 configures a partial RLC entitywith respect to the corresponding bearer and transmits the controlinformation on the successful reception of the PDCP PDUs, theaggregation entity may receive the same through a partial RLC entitythat is peered with it. In addition, when the terminal transmits thecontrol information on the successful reception of the PDCP PDUs throughthe PDCP entity with respect to the corresponding bearer, theaggregation entity may receive the same through a PDCP entity that ispeered with it.

Configuring and Using Partial RLC Protocol Operation

As described above, the interface connected between the base station andthe terminal through a WLAN carrier will be defined and denoted as an Uxinterface. When the user plane instance is configured between the basestation and WLAN termination in the user plane entity described above,the UP protocol entity may be configured to provide some of thefunctions (for example, an RLC status reporting function) for the ARQprocedure of the RLC layer. That is, some of the functions (for example,the RLC status reporting function) for the ARQ procedure of the typicalRLC layer may be provided through a new user plane entity (for example,a user plane sub-layer entity) in the terminal. In the case of theLTE-WLAN aggregation, this may be a user plane entity separated from theRLC entity for processing the PDCP PDUs received through the LTEwireless link. For example, this may be referred to as a WLAN RLC entityseparated from the LTE RLC entity. Hereinafter, this will be referred toas a user plane entity for the convenience of explanation. This is onlyfor the convenience and ease of understanding, and embodiments of thepresent disclosure are not limited thereto.

The user plane entity may transmit the PDCP PDUs to its peered userplane entity. In addition, the user plane entity may be configured toprovide the control information for providing theindication/acknowledgment for a successful delivery of the PDCP PDUs inthe Ux interface.

For example, in the case of the downlink transmission, the user planeentity of the base station may transmit the PDCP PDUs to the user planeentity of the terminal. The terminal user plane entity may provide thebase station with the control information containing theindication/acknowledgment information on a successful delivery of thedownlink PDCP PDUs. That is, the user plane entity of the terminal maytransmit, to the WLAN termination, the control information containingthe indication/acknowledgment information on a successful delivery ofthe downlink PDCP PDUs. The WLAN termination may transfer the same tothe user plane entity of the base station.

As another example, in the case of the downlink transmission, the userplane entity of the WLAN termination may transmit the PDCP PDUs receivedfrom the base station to the user plane entity of the terminal. Theterminal user plane entity may transmit, to the user plane entity of theWLAN termination, the control information containing theindication/acknowledgment information on a successful delivery of thedownlink PDCP PDUs. The user plane entity of the WLAN termination maytransfer the same to the base station. That is, the user plane entity ofthe terminal may transmit, to the base station, the control informationcontaining the indication/acknowledgment information on a successfuldelivery of the downlink PDCP PDUs through the WLAN termination.

For example, the status reporting may be triggered whenever its peereduser plane entity transmits the data. For example, in the case of thedownlink data transmission, the user plane entity of the terminal maytrigger the status reporting whenever the data is received.

As another example, the status reporting may be triggered in a periodset by the base station. For example, in the case of the downlink datatransmission, the user plane entity of the terminal may trigger thestatus reporting in a period set by the base station.

As another example, the status reporting may be triggered by the pollingfrom its peered user plane entity. For example, in the case of thedownlink data transmission, the user plane entity of the terminal maytrigger the status reporting by the polling of the user plane entity ofthe base station or by the polling of the user plane entity of the WLANtermination. To this end, the Ux UP protocol/UP protocol header may havea polling field, and when Ux UP PDU/UP PDU having a set polling field isreceived, the status reporting may be triggered.

As another example, the status reporting may be triggered when areception failure of one Ux UP PDU/UP PDU is detected. For example, inthe case of the downlink data transmission, when the user plane entityof the terminal receives Ux UP PDU that is out of sequence, the timermay be initiated. When the timer expires, the user plane entity of theterminal may trigger the status reporting.

The base station may include the configuration information forindicating a user plane entity that performs the partial RLC functiondescribed above in an RRC reconfiguration message to be transmitted tothe terminal. When the user plane entity is configured according to theconfiguration information of the base station, the terminal thatperforms the partial RLC function through the user plane entity may beconfigured to provide the base station with the control informationcontaining the indication/acknowledgment information for a successfuldelivery of the downlink PDCP PDUs. That is, the user plane entity ofthe terminal may transmit, to the WLAN termination, the controlinformation containing the indication/acknowledgment information on asuccessful delivery of the downlink PDCP PDUs. The WLAN termination maytransfer the same to the user plane entity of the base station.

In the case of the downlink transmission, the base station or the WLANtermination may remove buffered PDCP PDUs according to the feedback ofthe PDCP PDUs that are successfully delivered. In the case of the uplinktransmission, the terminal may remove buffered PDCP PDUs according tothe feedback of the PDCP PDUs that are successfully delivered.

The Ux UP protocol data/UP protocol data or Ux UP PDU(s)/UP PDU may beincluded in the GTP-U protocol/IP protocol/WLAN MAC protocol data field.Alternatively, the Ux UP protocol data/UP protocol data or Ux UPPDU(s)/UP PDU(s) may be included in the GTP-U protocol/IP protocol/MACprotocol payload. The Ux UP protocol header/UP protocol header mayinclude a field that separates the user plane data (PDCP PDUs) with thecontrol plane data (feedback).

The tunnel endpoint identification information (for example, TEID)included in the tunnel protocol header (for example, a GTP header or aheader in a certain header encapsulation-based tunnel) may be configuredto demultiplex the incoming traffic and to transfer the same to thecorresponding user plane entity.

For example, when the base station user plane entity splits data into orinterworks first data to be transmitted through an E-UTRAN carrierand/or second data to be transmitted through a WLAN carrier, theterminal that receives the data through the downlink tunnel or throughthe WLAN termination that is connected through the downlink tunnel maytransfer the PDCP PDUs to the peered or corresponding user plane entityin the terminal through the tunnel endpoint identificationinformation/the identification information included in the UP protocolfield.

As another example, when the terminal user plane entity interworks thedata to transmit the same through a WLAN carrier, the base station thatreceives the data through the uplink tunnel or through the WLANtermination that is connected through the uplink tunnel may transfer thePDCP PDUs to the peered or corresponding user plane entity in the basestation through the tunnel endpoint identification information.

As another example, when the base station PDCP entity splits data intoor interworks first data to be transmitted through an E-UTRAN carrierand/or second data to be transmitted through a WLAN carrier andtransmits the same, the terminal that receives data through the downlinktunnel or through the WLAN termination that is connected through thedownlink tunnel may transfer the PDCP PDUs to the peered orcorresponding PDCP entity in the terminal through the tunnel endpointidentification information/the identification information included inthe UP protocol field.

Usage of PDCP Control PDUs

As described above, the interface connected between the base station andthe terminal through the WLAN will be defined and denoted as an Uxinterface. The PDCP entity may provide the control information toprovide the indication/acknowledgment for a successful delivery of thePDCP SDUs/PDUs in the Ux interface.

For example, in the case of the downlink data transmission, the terminalmay detect whether the PDCP SDUs/PDUs that are received through the Uxinterface have been lost constantly or according to a constant periodset by the base station, a request of the base station, or a pollingfield setting included in the PDCP header from the base station. If thePDCP SDUs/PDUs are detected to be out of sequence or to have been lost,the terminal may transmit, to the base station, the highest PDCPsequence number that is successfully received. Alternatively, theterminal may transmit, to the base station, the highest PDCP sequencenumber that is successfully received constantly, according to a constantperiod set by the base station, according to a request of the basestation, or according to a polling field setting included in the PDCPheader from the base station. Alternatively, the terminal may detectwhether the PDCP SDUs/PDUs that are received through the Ux interfacehave been lost constantly, according to a constant period set by thebase station, according to a request of the base station, or accordingto a polling field setting. If the PDCP SDUs/PDUs are detected to be outof sequence or to have been lost, the terminal may transmit, to the basestation, the sequence numbers of the PDCP PDUs that are declared to havebeen lost by the terminal. Alternatively, the terminal may transmit, tothe base station, the sequence numbers of the PDCP SDUs/PDUs that aredeclared to have been lost by the terminal constantly or according to, aconstant period set by the base station, a request of the base station,or a polling field setting.

As described above, the information on the highest PDCP sequence numberthat is successfully received or the information on the sequence numbersof the PDCP SDUs/PDUs that are declared as being lost by the terminalmay be included in the control information for theindication/acknowledgment for the successful reception of the datadescribed above.

For example, the control information may be transmitted through theuplink Ux interface. As another example, the control information may betransmitted through the uplink Uu interface between the base station andthe terminal. For example, the control information may be transmitted byusing a PDCP status report. Alternatively, the control information maybe transmitted through a new format of PDCP control PDU.

Meanwhile, the terminal may declare the PDCP SDU/PDU as being lost,which has not been received: in a constant period set by the basestation; by a request of the base station; by a polling field settingthat is included in the PDCP SDU/PDU header from the base station;constantly; after the terminal receives the PDCP SDU/PDU that is out ofsequence; or after the lapse of expiration time set by the base stationsince the terminal receives the PDCP SDU/PDU that is out of sequence.

In the case of the downlink transmission, the base station may removebuffered PDCP SDUs/PDUs according to the feedback of the PDCP SDUs/PDUsthat are successfully delivered. In the case of the uplink transmission,the terminal may remove buffered PDCP SDUs/PDUs according to thefeedback of the PDCP SDUs/PDUs that are successfully delivered.

The base station may configure, in the terminal, the information thatinstructs to transmit the control information on theindication/acknowledgment for a successful delivery of the PDCPSDUs/PDUs in the Ux interface by using the PDCP control SDUs/PDUs.Alternatively, the base station may configure, in the terminal, theinformation that instructs to provide the control information on theindication/acknowledgment for a successful delivery of the PDCPSDUs/PDUs by using the PDCP control SDUs/PDUs. The base station mayinclude the information that instructs to transmit the controlinformation on the indication/acknowledgment for a successful deliveryof the PDCP SDUs/PDUs in the Ux interface by using the PDCP controlSDUs/PDUs and/or the information (for example, a timer, PollPDU, orPollByte) that is related to the same in the radio bearer configurationinformation (DRB-ToAddMod) or in the PDCP configuration information(PDCP-CONFIG), and may transmit the same.

Until now, the operations of transmitting data by using a WLAN carrierand transmitting the control information to acknowledge a successfuldelivery of the data, according to the embodiment of the presentdisclosure, have been described. For the convenience of explanation, thedescription above has been made of the case where the terminal receivesthe downlink data by using a WLAN carrier. However, the embodimentsdescribed above may also be applied to the case where the base stationreceives the uplink data by using a WLAN carrier with the replacement ofthe entity.

Hereinafter, the operation of the base station will be described withreference to the drawings in relation to the case where the terminalreceives the downlink data. Of course, the description described belowmay also be applied to the case where the terminal transmits the uplinkdata with the replacement of the entity (base station) by the terminal.

FIG. 24 is a flowchart for explaining operation of a base station,according to an embodiment of the present disclosure.

The base station, according to another embodiment of the presentdisclosure, may execute the steps of: configuring an interface and auser plane entity for transmitting or receiving data to or from theterminal through a WLAN carrier; transmitting user plane data to theterminal through an interface; and receiving, from the terminal, controlinformation indicating the successful or unsuccessful reception of theuser plane data through the interface or the interface between theterminal and the base station.

Referring to FIG. 24, the base station may execute configuring aninterface and a user plane entity for transmitting or receiving data toor from the terminal through a WLAN carrier (S2410). For example, thebase station of the present disclosure may configure a datatransmission/reception interface with the terminal by using a WLANcarrier. As shown in the scenarios described with reference to FIG. 16to FIG. 19, the base station of the present disclosure may configure adata transmission/reception interface through a WLAN carrier for each ofa variety of scenarios. For example, the base station may configure aninterface for transmitting the downlink data that is transmitted to theterminal through a WLAN termination. Alternatively, the base station mayalso configure an interface for receiving the uplink data through a WLANtermination. Alternatively, the base station may configure an interfacefor transmitting or receiving data to or from the terminal by using boththe E-UTRAN carrier and the WLAN carrier.

Meanwhile, the base station may configure a user plane entity totransmit or receive data through a WLAN carrier. The user plane entityrefers to a functional entity for transmitting or receiving data byusing a WLAN carrier, and may be configured with an entity that ispeered with the terminal.

In addition, the user plane entity may be configured to be associatedwith each data radio bearer. That is, it may be determined whether theuser plane entity is configured for each data radio bearer. For example,the user plane entity may not be configured in the case of a data radiobearer that does not use a WLAN carrier, and the user plane entity maybe configured only in the case of a data radio bearer using a WLANcarrier.

The base station may transmit configuration information for configuringthe user plane entity to the terminal. The configuration information forconfiguring the user plane entity may be included in the radio bearerconfiguration information to then be received. That is, each piece ofthe radio bearer configuration information may include the configurationinformation for the user plane entity that is configured for each radiobearer. For example, in the case of a radio bearer that transmits orreceives data only by using the E-UTRAN carrier, the radio bearerconfiguration information may not include the configuration informationfor configuring the user plane entity. On the contrary, in the case of adata radio bearer that uses a WLAN carrier, the radio bearerconfiguration information may include the configuration information forconfiguring the user plane entity. The radio bearer configurationinformation may be transmitted through an upper layer signaling. Forexample, the radio bearer configuration information may be included inan RRC message, such as an RRC connection reconfiguring message, to thenbe transmitted.

The base station may execute transmitting the user plane data to theterminal through the interface (S2420). For example, as described withreference to FIG. 16 to FIG. 19, the base station may transmit the userplane data through a WLAN carrier according to each scenario. In thiscase, the data may be transmitted through the interface that isconfigured in the step S2410 and uses a WLAN carrier. That is, the basestation may process the data to be transmitted through the WLAN carrierby means of the user plane entity.

The base station may execute receiving, from the terminal, the controlinformation indicating the successful or unsuccessful reception of theuser plane data through the interface or through the interface betweenthe terminal and the base station (S2430). For example, the controlinformation may include information that acknowledges or indicates thesuccessful reception of the data transmitted by the PDCP entitydescribed above. That is, the terminal may transmit, to the basestation, the control information that includes the informationindicating whether the data is successfully received through the WLANcarrier, and the base station may receive the control information.

In this case, the control information may be provided from the userplane entity or the PDCP entity. For example, the user plane entity ofthe terminal may check whether the PDCP PDU has been successfullyreceived. If the PDCP PDU is missing or is received out of sequence, theuser plane entity may include information on the same in the controlinformation and transmitted to the base station. Alternatively, the PDCPentity of the terminal may check whether the PDCP PDU has beensuccessfully received. If the PDCP PDU is missing or is received out ofsequence, the PDCP entity may include information on the same in thecontrol information and be transmitted to the base station.Alternatively, the transmission of the control information may betriggered based on the polling of the base station, a period set by thebase station, or a timer set by the same. In this case, the base stationmay transmit the period or timer information for transmitting thecontrol information in advance.

Meanwhile, the control information may be received by the base stationthrough an interface that is configured to process the data by using aWLAN carrier. Alternatively, the control information may be received bythe base station through an interface between the terminal and the basestation neither of which use a WLAN carrier. That is, the controlinformation may be received through an interface using the WLAN carrier,or may be received through an interface using only the E-UTRAN carrier.

The present disclosure described above will also provide an effect inwhich the typical PDCP function can be operated in the same manner evenwhen the base station and the terminal add the WLAN carrier to thentransmit or receive the data. In addition, the present disclosure alsoprovides an effect in which the retransmission procedure can be executedby identifying the completion of the reception of data even when thebase station and the terminal add the WLAN carrier to then transmit orreceive the data.

The configurations of the terminal and the base station that can executethe embodiments of the present disclosure will be described withreference to the drawings.

FIG. 25 illustrates a terminal, according to an embodiment of thepresent disclosure.

Referring to FIG. 25, the terminal 2500, according to an embodiment ofthe present disclosure, may include: a controller 2510 that configuresan interface and a user plane entity for transmitting or receiving datato or from the base station through a WLAN carrier; a receiving unit2530 that receives user plane data from the base station through theinterface; and a transmitting unit 2520 that transmits, to the basestation, the control information indicating the successful orunsuccessful reception of the user plane data through the interface orthrough the interface between the terminal and the base station.

In addition, the controller 2510 may be associated with each data radiobearer to configure a user plane entity. The controller 2510 may controlthe overall operations of the terminal that executes the presentdisclosure described above for transmitting specific user plane data,wherein the operations include: adding a WLAN carrier as a carrier tothe E-UTRAN; and performing a split or interworking function withrespect to the user plane data in the PDCP layer, which is necessary forthe transmission of the user plane data through an E-UTRAN carrierand/or a WLAN carrier.

The receiving unit 2530 may receive the radio bearer configurationinformation including the configuration information for configuring theuser plane entity through an upper layer signaling. Furthermore, thereceiving unit 2530 receives downlink control information, data, ormessages from the base station through the corresponding channel.

The transmitting unit 2520 may transmit the control informationcontaining the information on the indication/acknowledgment for thesuccessful reception of the data by using an interface through the WLANcarrier or through an interface between the terminal and the basestation. The control information may be provided from the user planeentity or the PDCP entity. The control information may be triggeredbased on at least one of the polling of the base station or a period ortimer that is set by the base station. The transmitting unit 2520transmits, to the base station, uplink control information, data, ormessages through the corresponding channel.

In addition, the controller 2510, the transmitting unit 2520, and thereceiving unit 2530 may perform all of the operations of the terminal2500 necessary for the execution of the present disclosure describedwith reference to FIGS. 16 to 24.

FIG. 26 illustrates a base station, according to an embodiment of thepresent disclosure.

Referring to FIG. 26, the base station 2600, according to an embodimentof the present disclosure, may include: a controller 2610 thatconfigures an interface and a user plane entity for transmitting orreceiving data to or from a terminal through a WLAN carrier; atransmitting unit 2620 that transmits user plane data to the terminalthrough the interface; and a receiving unit 2630 that receives, from theterminal, the control information indicating the successful orunsuccessful reception of the user plane data through the interface orthrough the interface between the terminal and the base station.

The controller 2610 may be associated with each data radio bearer toconfigure a user plane entity. In addition, the controller 2610 maycontrol the overall operations of the base station 2600 that executesthe at least one embodiment of the present disclosure described abovefor transmitting or receiving specific user plane data, wherein theoperations include: adding a WLAN carrier as a carrier to the E-UTRAN;and performing a split or interworking function with respect to the userplane data unit in the PDCP layer, which is necessary for thetransmission and reception of the user plane data through the E-UTRANcarrier and/or the WLAN carrier.

The transmitting unit 2620 may transmit, to the terminal, the radiobearer configuration information including the configuration informationfor configuring the user plane entity through an upper layer signaling.

The receiving unit 2630 may receive, from the terminal, the controlinformation indicating the successful or unsuccessful reception of theuser plane data through the interface or through the interface betweenthe terminal and the base station. The control information may beprovided from the user plane entity or the PDCP entity of the terminal.In addition, the control information may be triggered based on at leastone of the polling of the base station or a period or timer that is setby the base station.

Furthermore, the transmitting unit 2620 and the receiving unit 2630 maybe used to transmit or receive signals, messages, or data necessary forthe execution of the present disclosure described above.

The standard content or standard documents, which have been omitted forthe simplicity of the description in the embodiments described above,are incorporated in the present specification. Therefore, the additionor insertion of some of the standard content or standard documents tothe present specification or the claims should be construed to fallwithin the scope of the invention.

Although a preferred embodiment of the present disclosure has beendescribed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions, and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims. Therefore, the embodimentsdisclosed in the present disclosure are intended to illustrate the scopeof the technical idea of the present disclosure, and the scope of thepresent disclosure is not limited by the embodiment. The scope of thepresent disclosure shall be construed on the basis of the accompanyingclaims in such a manner that all of the technical ideas included withinthe scope equivalent to the claims belong to the present disclosure.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit under 35 U.S.C. §119(a) of Korean Patent Application Nos. 10-2014-0124570, filed on Sep.18, 2014, 10-2014-0133265, filed on Oct. 2, 2014, 10-2015-0067822, filedon May 15, 2015, 10-2015-0114273, filed on Aug. 13, 2015, and10-2015-0114278, filed on Aug. 13, 2015 which are hereby incorporated byreference for all purposes as if fully set forth herein. Also, when thisapplication claims the priority benefit of the same Korean PatentApplications from countries in addition to the U.S., the disclosure willbe incorporated herein by reference.

The invention claimed is:
 1. A method for processing data by a terminal,the method comprising: configuring a user plane entity for receivingdata from a base station through a wireless local area network (WLAN)carrier, wherein the user plane entity is configured as a separateentity from a packet data convergence protocol (PDCP) entity; receiving,by the user plane entity, user plane data from the base station throughthe WLAN carrier; and transmitting control information indicatingsuccessful or unsuccessful reception of the user plane data through theWLAN carrier to the base station through an interface between theterminal and the base station.
 2. The method according to claim 1,wherein the user plane entity is configured in a lower layer of a PDCPlayer.
 3. The method according to claim 1, further comprising receivingradio bearer configuration information or PDCP configuration informationincluding parameters for transmission of the control information throughan upper layer signaling, wherein the parameters for the transmission ofthe control information include at least one piece of informationinstructing the transmission of the control information, information ona transmission method of the control information, or information on atransmission period thereof.
 4. The method according to claim 1, whereinthe control information is provided from at least one of the user planeentity and the PDCP entity.
 5. The method according to claim 1, whereinthe transmission of the control information is triggered based on atleast one of polling of the base station, a period and a timer, which isset by the base station.
 6. A method for processing data by a basestation, the method comprising: configuring a user plane entity fortransmitting data to a terminal through a wireless local area network(WLAN) carrier, wherein the user plane entity is configured as aseparate entity from a packet data convergence protocol (PDCP) entity;transmitting, by the user plane entity, user plane data to the terminalthrough the WLAN carrier; and receiving control information indicatingsuccessful or unsuccessful reception of the user plane data through theWLAN carrier from the terminal through an interface between the terminaland the base station.
 7. The method according to claim 6, wherein theuser plane entity is configured in a lower layer of a PDCP layer.
 8. Themethod according to claim 6, further comprising transmitting radiobearer configuration information or PDCP configuration informationincluding parameters for transmission of the control information of theterminal through an upper layer signaling, wherein the parameters forthe control information transmission include at least one piece ofinformation instructing the transmission of the control information,information on a transmission method of the control information, andinformation on a transmission period thereof.
 9. The method according toclaim 6, wherein the control information is provided from at least oneof the user plane entity and a PDCP entity of the terminal.
 10. Themethod according to claim 6, wherein the transmission of the controlinformation is triggered based on at least one of polling of the basestation, a period, and a timer, which is set by the base station.
 11. Aterminal for processing data, the terminal comprising: a controllerconfigured to configure a user plane entity for receiving data from abase station through a wireless local area network (WLAN) carrier,wherein the user plane entity is configured as a separate entity from apacket data convergence protocol (PDCP) entity; a receiving unitconfigured to receive, by the user plane entity, user plane data fromthe base station through the WLAN carrier; and a transmitting unitconfigured to transmit control information indicating successful orunsuccessful reception of the user plane data through the WLAN carrierto the base station through an interface between the terminal and thebase station.
 12. The terminal according to claim 11, wherein the userplane entity is configured in a lower layer of a PDCP layer.
 13. Theterminal according to claim 11, wherein the receiving unit is configuredto receive radio bearer configuration information or PDCP configurationinformation including parameters for transmission of the controlinformation through an upper layer signaling, wherein the parameters forthe transmission of the control information include at least one pieceof information instructing the transmission of the control information,information on a transmission method of the control information, andinformation on a transmission period thereof.
 14. The terminal accordingto claim 11, wherein the control information is provided from at leastone of the user plane entity and the PDCP entity.
 15. The terminalaccording to claim 11, wherein the transmission of the controlinformation is triggered based on at least one of polling of the basestation, a period, and a timer, which is set by the base station.